/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr, /* for address of replaced block */
tick_t *mem_ready/* ptr to mem_ready of ruu_station */
)
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
md_addr_t blk_addr = CACHE_TAGSET(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
int i,mshr_hit = -1;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
/// printf("mshr enabled=%d\n",mshr_enabled);
//printf("cache_access miss num_mshr=%d\n",cp->num_mshr);
//printf("cache_access with MSHR\n");
// search mshr first to see if already exists, if so wait
// if not in mshr, insert
if (cp->num_mshr>0) {
cp->mshr_accesses++;
for (i = 0; i < cp->num_mshr; i++) {
if (cp->mshr[i].ready <= now) {
/* we have an empty mshr, so we can proceed with the miss */
mshr_hit = i;
cp->mshr_misses++;
//printf("MSHR:miss=%d",cp->mshr_misses);
break;
}
}
if (mshr_hit == -1) { /* no empty mshr, so stall! */
cp->mshr_full++;
if(mem_ready!=NULL)*mem_ready = cp->ready;
//if (cp->ready <= now) panic("Should have had empty mshr!");
return MSHR_FULL;
}
}
//printf("B4 repl\n");
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
// printf("B4 blkaccess\n");
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* populate mshr entries*/
if (cp->num_mshr>0 && mshr_hit!=-1) {
cp->mshr[mshr_hit].ready = repl->ready;
cp->mshr[mshr_hit].block_addr= blk_addr;
cp->mshr[mshr_hit].target_num = 1;
// printf("MSHR:ready and block_addr=",repl->ready,blk_addr);
for (i = 0, cp->ready = cp->mshr[0].ready; i < cp->num_mshr; i++) {
if (cp->mshr[i].ready < cp->ready)
cp->ready = cp->mshr[i].ready;
}
}
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* mshr: check for secondary miss */
if (cp->num_mshr>0) {
/* is this a secondary miss? */
if (blk->ready > now) {
/* search for matching mshr */
cp->mshr_accesses++;
for (i = 0; i < cp->num_mshr; i++) {
if (cp->mshr[i].block_addr == blk_addr && cp->mshr[i].ready > now) {
if (cp->mshr[i].target_num < 4) {
mshr_hit = i;
cp->mshr[i].target_num++;
cp->mshr_hits++;
break;
}
else {
/* target space full, so stall! */
if(mem_ready!=NULL)*mem_ready = cp->mshr[i].ready;
cp->mshr_target_full++;
return MSHR_TARGET_FULL;
}
}
}
}
}
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* mshr: check for secondary miss */
if (cp->num_mshr>0) {
/* is this a secondary miss? */
if (blk->ready > now) {
cp->mshr_accesses++;
/* search for matching mshr */
for (i = 0; i < cp->num_mshr; i++) {
if (cp->mshr[i].block_addr == blk_addr && cp->mshr[i].ready > now) {
if (cp->mshr[i].target_num < 4) {
mshr_hit = i;
cp->mshr[i].target_num++;
cp->mshr_hits++;
break;
}
else {
/* target space full, so stall! */
if(mem_ready!=NULL)*mem_ready = cp->mshr[i].ready;
cp->mshr_target_full++;
return MSHR_TARGET_FULL;
}
}
}
}
}
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
struct pdp_fifo_node *fnode, *tnode;
int lat = 0;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* PDP distance decrement on set access */
if(cp->policy == PDP){
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->rpd > 0) blk->rpd--;
}
/* PDP counter update */
cp->PDP_Nt++;
if((cp->PDP_Nt % 50000) == 0) compute_pd(cp);
}
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
case PDP:
{
int bindex, nindex=-1, iindex=1, rindex=1, max_irpd=-1, max_rrpd=-1;
for (bindex=cp->assoc-1, blk=cp->sets[set].way_head;
blk;
bindex--, blk=blk->way_next)
{
// if(blk->rpd!=0) printf("BLK: %d, RPD: %d\n", bindex, blk->rpd);
/* victim is the first-found unprotected line */
if(blk->rpd == 0) {
nindex = bindex;
break;
}
/* victim selection if there are no unprotected lines */
/* replace inserted line with highest rpd, if none found replace reused line with highest rpd */
if(blk->rpd > max_irpd){
if(blk->reused == 0){
max_irpd = blk->rpd;
iindex = bindex;
}
}
if(blk->rpd > max_rrpd){
if(blk->reused == 1){
max_rrpd = blk->rpd;
rindex = bindex;
}
}
}
if(nindex==-1) {
nindex = ((max_irpd == -1) ? rindex : iindex);
repl = cp->sets[set].way_tail;
}
else repl = CACHE_BINDEX(cp, cp->sets[set].blks, nindex);
update_way_list(&cp->sets[set], repl, Head);
repl->rpd = PDP_PD - 1; /* PDP distance decrement on block replacement */
repl->reused = 0;
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && ((cp->policy == LRU) || (cp->policy == PDP)))
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* PDP reuse routine */
if(cp->policy == PDP){
blk->rpd = PDP_PD - 1;
blk->reused = 1;
/* RD sampler and PDP counter updates */
int rd;
for (rd=0, fnode=cp->sets[set].fifo_head;
fnode;
fnode=fnode->next)
{
if(fnode->address == addr){
//printf("%d ", rd);
cp->PDP_Ni[rd]++;
break;
}
rd++;
}
/* Push the address to head of FIFO */
struct pdp_fifo_node * pnode = (struct pdp_fifo_node *)malloc(sizeof(struct pdp_fifo_node));
pnode->address = addr;
tnode = cp->sets[set].fifo_head;
if(tnode) tnode->prev = pnode;
pnode->next = tnode;
pnode->prev = NULL;
cp->sets[set].fifo_head = pnode;
if(!tnode) cp->sets[set].fifo_tail = cp->sets[set].fifo_head;
/* truncate fifo on overflow */
if(cp->sets[set].nfifo == PDP_PD_MAX){
fnode = cp->sets[set].fifo_tail;
if(fnode){
if(fnode->prev){
fnode->prev->next = NULL;
cp->sets[set].fifo_tail = fnode->prev;
}
free(fnode);
}
}
else cp->sets[set].nfifo++;
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* PDP reuse routine */
if(cp->policy == PDP){
blk->rpd = PDP_PD - 1;
blk->reused = 1;
/* previously hit block, so distance is zero; skipping fifo update */
cp->PDP_Ni[0]++;
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
acheck++;
//printf("%d \n",acheck);
byte_t *p = vp;
md_addr_t tag;
if (pseudo_check==1)
tag = CACHE_TAG_PSEUDOASSOC(cp, addr);
else
tag= CACHE_TAG(cp,addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
md_addr_t set1=HASH_MASK(set);
md_addr_t addr1=addr;
addr1 ^=1<<(cp->set_shift);
//set1=CACHE_SET(cp,addr1);
struct cache_blk_t *blk, *repl;
int lat = 0;
// if (cp->sets[set].rehash_bit==1)
//printf("yo");
//printf("%d",cp->sets[set].way_head->rehash_bit );
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
//printf("same block hit");
blk = cp->last_blk;
//cp->last_blk->rehash_bit=0;
goto cache_fast_hit;
}
if (cp->hsize)
{
//printf("different block hit");
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{ //printf("different block hit");
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
{
goto cache_hit;
}
}
}
/* cache block not found */
/* **MISS** */
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
if(pseudo_check==1)
{ //printf("%d",hash_check);
if(cp->sets[set].way_head->rehash_bit==1 )
{//printf("hii");
if(hash_check==1)
{ cp->sets[set].way_head->rehash_bit=1;
goto cache_missfinal;
}
else if(hash_check==0)
{
cp->sets[set].way_head->rehash_bit=0;
goto cache_missfinal;
}
}
if(cp->sets[set].way_head->rehash_bit==0)
{ //printf("hello");
if(hash_check==1)
{ cp->sets[set].way_head->rehash_bit=1;
temp=cp->sets[set].way_head;
goto cache_missfinal;
}
else if(hash_check==0)
{
hash_check=1;
cache_access(cp,cmd,addr1,NULL,nbytes,now,NULL,NULL);
//goto cache_missfinal;
}
}
//unsigned int uff=0;
temp1=cp->sets[set].way_head;
temp1->tag=temp->tag;
if(temp->status!=3)
temp1->status=temp->status;//temp->status;
//printf("%u",temp1->status);
temp1->ready=temp->ready;
temp->tag=cp->sets[set].way_head->tag;
temp->status=cp->sets[set].way_head->status;
temp->ready=cp->sets[set].way_head->ready;
cp->sets[set].way_head->tag=temp1->tag;
cp->sets[set].way_head->status=temp1->status;
cp->sets[set].way_head->ready=temp1->ready;
//printf("%d",temp->rehash_bit);
}
cache_missfinal:
hash_check=0;
cp->misses++;
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
int possible_real_miss = 0;
int low_leak_penalty_flag =0;
int temp;
int decay_caused_miss = FALSE; /* TRUE if it's a decay caused miss */
if (b_in_dispatch)
b_in_dispatch = TRUE;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if ((blk->status & CACHE_BLK_DECAYED) && cache_leak_is_ctrlled())
low_leak_penalty_flag = 1;
if (blk->tag == tag)
{
/* Leakage: induced misses only in state losing ctrl techniques */
if ((blk->status & CACHE_BLK_DECAYED) && cache_leak_ctrl_is_state_losing())
{
decay_caused_miss = TRUE;
induced_decay_misses++;
break;
}
else if ((blk->status & CACHE_BLK_DECAYED) && (blk->status & CACHE_BLK_VALID)\
&& cache_leak_is_ctrlled())
{
/*
* Leakage: update stats
* in state preserving ctrl, mode switch to high happens
* on a hit to a decayed block too
*/
mode_switch_l2h_incr ();
/*
* leakage throughout the cache assumed uniform. Also to model
* the effect of settling time of leakage current, the lines
* are assumed to be turned off after 'switch_cycles_l2h/2'.
* The assumption is that settling is a linear function of time.
*/
low_leak_ratio_dcr(1.0/(cp->nsets * cp->assoc), get_switch_cycles_l2h()/2);
goto cache_hit;
}
else if( blk->status & CACHE_BLK_VALID)
goto cache_hit;
}
else
if (blk->status & CACHE_BLK_DECAYED)
possible_real_miss = 1;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if ((blk->status & CACHE_BLK_DECAYED) && cache_leak_is_ctrlled())
low_leak_penalty_flag = 1;
if (blk->tag == tag)
{
/* Leakage: induced misses only in state losing ctrl techniques */
if ((blk->status & CACHE_BLK_DECAYED) && cache_leak_ctrl_is_state_losing())
{
decay_caused_miss = TRUE;
if (cp == decayed_cache)
{
induced_decay_misses++;
break;
}
}
else if ((blk->status & CACHE_BLK_DECAYED) && (blk->status & CACHE_BLK_VALID)\
&& cache_leak_is_ctrlled())
{
/*
* Leakage: update stats
* in state preserving ctrl, mode switch to high happens
* on a hit to a decayed block too
*/
mode_switch_l2h_incr ();
/*
* leakage throughout the cache assumed uniform. Also to model
* the effect of settling time of leakage current, the lines
* are assumed to be turned off after 'switch_cycles_l2h/2'.
* The assumption is that settling is a linear function of time.
*/
low_leak_ratio_dcr(1.0/(cp->nsets * cp->assoc), get_switch_cycles_l2h()/2);
goto cache_hit;
}
else if( blk->status & CACHE_BLK_VALID)
goto cache_hit;
}
else
if (blk->status & CACHE_BLK_DECAYED)
possible_real_miss = 1;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
if (cmd == Write) cp->write_misses++;
else cp->read_misses++;
if (cp == decayed_cache && !decay_caused_miss && possible_real_miss)
real_decay_misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
/* FIXMEHZG: replacement policy: choose invalid block first, does this diff from LRU? */
#if defined(cache_decay)
if(b_decay_enabled)
{
int k, found=0;
for (blk=cp->sets[set].blks, k=0; k< cp->assoc; blk++, k++)
{
/* invalid block has highest priority to be evicted */
if (!(blk->status & CACHE_BLK_VALID))
{
repl = blk;
found=1;
break;
}
}
/* Leakage: if an invalid blk can't be found, find a shutdown one */
if (!found && cache_leak_ctrl_is_state_losing())
for (blk=cp->sets[set].blks, k=0; k< cp->assoc; blk++, k++)
{
/* invalid block has highest priority to be evicted */
if (blk->status & CACHE_BLK_DECAYED)
{
repl = blk;
break;
}
}
}
#endif /* defined(cache_decay) */
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
if (low_leak_penalty_flag == 1 && /* repl-> status & CACHE_BLK_DECAYED */ cache_leak_is_ctrlled() )
{
temp = get_low_leak_penalty();
/* latency hiding assumed */
lat += get_low_leak_penalty() ;
}
/* Leakage: update stats */
/* mode switch to high happens if block to be evicted is decayed*/
if (repl->status & CACHE_BLK_DECAYED)
{
mode_switch_l2h_incr ();
/*
* leakage throughout the cache assumed uniform. Also to model
* the effect of settling time of leakage current, the lines
* are assumed to be turned off after 'switch_cycles_l2h/2'.
* The assumption is that settling is a linear function of time.
*/
low_leak_ratio_dcr(1.0/(cp->nsets * cp->assoc), get_switch_cycles_l2h()/2);
}
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}/* if */
if (b_decay_profile_enabled)
update_cache_block_stats_when_miss(cp, repl, cmd, decay_caused_miss);
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
repl->status &= ~CACHE_BLK_DECAYED; /* not decayed */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize, repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
{
repl->status |= CACHE_BLK_DIRTY;
repl->time_dirty = sim_cycle;
}
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* Leakage: for misses in low leak mode */
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* Leakage: for hits in low leak mode */
if (blk-> status & CACHE_BLK_DECAYED && cache_leak_is_ctrlled() )
{
blk->status &= ~CACHE_BLK_DECAYED;
temp = get_low_leak_penalty();
/* latency hiding assumed */
if (blk->ready < now + get_low_leak_penalty ())
blk->ready = now + get_low_leak_penalty() +cp->hit_latency ;
}
if (b_decay_profile_enabled)
update_cache_block_stats_when_hit(cp, blk, cmd);
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
{
blk->status |= CACHE_BLK_DIRTY;
blk->time_dirty = sim_cycle;
}
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* Leakage: for hits in low leak mode */
if (blk-> status & CACHE_BLK_DECAYED)
fatal ("can't have decayed block in fast_hit");
if (b_decay_profile_enabled)
update_cache_block_stats_when_hit(cp, blk, cmd);
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
{
blk->status |= CACHE_BLK_DIRTY;
blk->time_dirty = sim_cycle;
}
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}/* cache_access */
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
if(cp->isL2){
if(set > 512){
fprintf(stderr, "Houston we have a problem, set = %d\n", set);
scanf("%d", &lat);
}
}
int pointerLat = 0;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
/*FP-JS Loc will store the last line traversed through the list
I want to keep set so I know where the head of the list is for replacement
*/
unsigned int loc = set;
/*FP-BC Modified cache hit checker for new cache structure*/
if(cp->isL2)
{
/*FP-BC continue through each linked set with data*/
while(cp->sets[loc].usageCtr)
{
//if(cp->isL2)
//fprintf(stderr, "ptr = %d, loc = %d", cp->sets[loc].fwdPtr, loc);
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[loc].hash[hindex]; blk; blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID)){
//fprintf(stderr, "Hit!");
goto cache_hit;
}
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[loc].way_head; blk; blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID)){
// fprintf(stderr, "Hit!");
goto cache_hit;
}
}
}
/*FP-BC If the current set has a pointer to another set,
follow it and check again for a hit*/
if(cp->sets[loc].fwdPtr){
loc = cp->sets[loc].fwdPtr;
pointerLat+=1;
}
else
break;
}
}
/*FP-BC Original cache hit checker*/
else
{
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex]; blk; blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head; blk; blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
enum cache_policy policy = cp->policy;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
if(cp->isL2){
if(cp->sets[loc].fullBit == 0){
//fprintf(stderr, "FIFO\n" );
policy = FIFO; //use FIFO to fill the set
cp->sets[loc].usageCtr++;
if(loc != set)
cp->sets[set].usageCtr++;
if(cp->sets[loc].usageCtr == cp->assoc){
cp->sets[loc].fullBit = 1; // set full if adding to the set reached its assoc
}
set = loc;
}
else if(cp->fullFlag == 0){
int numSets = cp->sets[set].usageCtr/cp->assoc;
if(numSets < 5){ //only add a line if the linked list is less than 5 length
//fprintf(stderr, "adding a pointer. FSR = %d, loc = %d\n", cp->FSR, cp->nsets, numSets, loc);
policy = FIFO;
cp->sets[loc].usageCtr++;
if(loc != set)
cp->sets[set].usageCtr++;
cp->sets[loc].fwdPtr = cp->FSR;
if(loc == cp->FSR){
fprintf(stderr, "FSR = %d loc = %d\n", cp->FSR, loc);
// scanf("%s", &loc);
}
set = cp->FSR;
cp->FSR = 1 + (cp->FSR);
if(cp->FSR >= cp->nsets*2){
cp->fullFlag = 1;
}
}
else {
//fprintf(stderr, "more than 5 pointers\n");
int times = rand() % numSets;
int i = 0;
for(i = 0; i < times; i++){
if(cp->sets[set].fwdPtr != 0){
set = cp->sets[set].fwdPtr;
pointerLat+=1;
}
}
}
}
else{ //else everything is full so randomly select a set
//fprintf(stderr, "evicting a set\n");
int numSets = cp->sets[set].usageCtr/cp->assoc;
//fprintf(stderr, "numSets is %d\n", numSets);
int times = myrand();
times = times % numSets;
//fprintf(stderr, "times is %d\n", times);
int i = 0;
for(i = 0; i < times; i++){
if(cp->sets[set].fwdPtr != 0){
set = cp->sets[set].fwdPtr;
pointerLat+=1;
}
}
}
}
switch (policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
//fprintf(stderr, "here\n" );
int bindex = myrand();
bindex = bindex & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
//fprintf(stderr, "exiting\n" );
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat+pointerLat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata){
*udata = blk->user_data;
}
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency+pointerLat, pointerLat+(blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(pointerLat+cp->hit_latency, pointerLat+(blk->ready - now));
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
int victim; //DRRIP-Used in while loop to check if we found the victim block or not
int RRPV_counter;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk; //DRRIP-No need to make RRPV=0 here as the block is accessed previously, so in RRIP-HP it is already 0
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
{
blk->RRPV=0; //DRRIP-Implementing Re-Reference, when we encounter hit then make RRPV=0
//printf("Its a hit and now RRPV=%d\n", blk->RRPV);
goto cache_hit;
}
}
}
/* cache block not found */
/* **MISS***/
cp->misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case DRRIP:
RRPV_counter=1<<(cp->RRPV_bits);
//printf("Max choices=%d\n",RRPV_counter);
victim=0;
while(victim==0) //DRRIP-We keep on looking till the time we don't find the victim block
{
//DRRIP-Traversing code copied from hit policy line 559
for (blk=cp->sets[set].way_head;blk;blk=blk->way_next) //DRRIP-Resolves the tie breaker automatically
{
//printf("Value of RRPVin a set=%d\n",blk->RRPV);
if(blk->RRPV==RRPV_counter-1) //DRRIP-To check if we have a block on set with RRPV=3
{
victim=1;
repl=blk; //DRRIP-Address of the victim block assogned to block to be inserted
break;
}
}
if(victim==0) //DRRIP-Incase unable to find blk with RRPV=3
{
for (blk=cp->sets[set].way_head;blk;blk=blk->way_next) //DRRIP-Traverse the blocks and increment RRPV by 1
blk->RRPV++;
}
if(victim==1) //DRRIP-Work is done, now get out and update the parameters of inserted block
break;
}
//What to do now when we know that this is the blck to replace
//Now we will populate the elements of repl block with new data,tag,RRPV value.
//printf("Outside the while and victim=%d\n",victim);
//DRRIP-Update the RRPV value of the new inserted block for RRIP
if(set==0 || set%1024==0 || set%33==0)
{
// printf("Inside SRRIP with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-2;
// printf("Inside SRRIP with new RRPV=%d\n",repl->RRPV);
if(cp->PSEL<1023)
cp->PSEL++;
// printf("Inside srrip with psel=%d\n",cp->PSEL);
break;
}
else if(set%31==0)
{
if(cp->throttle1==31)
{
// printf("Inside BRRIP infrequent case with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-2;
// printf("Inside BRRIP infrequent case with new RRPV=%d\n",repl->RRPV);
cp->throttle1=0;
}
else
{
// printf("Inside BRRIP majority case with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-1;
// printf("Inside BRRIP majority case with new RRPV=%d\n",repl->RRPV);
cp->throttle1++;
}
if(cp->PSEL>0)
cp->PSEL--;
// printf("Value of throttle1=%d\n",cp->throttle1);
break;
}
else
{
// printf("In follower set with PSEL=%d\n",cp->PSEL);
if(cp->PSEL<511)
{
// printf("In follower SRRIP with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-2;
// printf("In follower SRRIP with new RRPV=%d\n",repl->RRPV);
break;
}
else
{
if(cp->throttle2==31)
{
// printf("Inside follower BRRIP infrequent case with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-2;
// printf("Inside follower BRRIP infrquent case with new RRPV=%d\n",repl->RRPV);
cp->throttle2=0;
}
else
{
// printf("Inside follower BRRIP majority case with original RRPV=%d\n",repl->RRPV);
repl->RRPV=RRPV_counter-1;
// printf("Inside follower BRRIP majority case with new RRPV=%d\n",repl->RRPV);
cp->throttle2++;
}
// printf("Value of throttle2=%d\n",cp->throttle2);
break;
}
} //End of DRRIP
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case DIP:
repl = cp->sets[set].way_tail;
enum list_loc_t where; /* insert location */
if ( cp->sets[set].DIP_set_type == LRU_set ) {
where = Head;
// update PSEL to bias BIP
int max_PSEL = 1 << cp->width_PSEL - 1;
if ( cp->PSEL < max_PSEL ) {
cp->PSEL ++;
}
}
else if ( cp->sets[set].DIP_set_type == BIP_set ) {
if ( cp->BIPCTR == 0 ) {
// use LRU policy, MRU insertion
where = Head;
}
else {
// use LIP policy, LRU insertion
where = Tail;
}
// update BIPCTR in a non-saturating way
// int max_BIPCTR = 1 << cp->width_BIPCTR - 1;
// if ( cp->BIPCTR < max_BIPCTR ) {
// cp->BIPCTR ++;
// }
// else {
// cp->BIPCTR = 0;
// }
// update PSEL to bias LRU
if ( cp->PSEL > 0 ) {
cp->PSEL --;
}
}
else {
// most significant bit of PSEL counter
int MSB_PSEL = cp->PSEL >> (cp->width_PSEL - 1);
if ( MSB_PSEL == 1 ) {
// use BIP
if ( cp->BIPCTR == 0 ) {
// use LRU policy, MRU insertion
where = Head;
}
else {
// use LIP policy, LRU insertion
where = Tail;
}
// need to update BIPCTR ?
}
else {
// use LRU
where = Head;
}
}
update_way_list(&cp->sets[set], repl, where);
// update BIPCTR in a non-saturating way
int max_BIPCTR = 1 << cp->width_BIPCTR - 1;
if ( cp->BIPCTR < max_BIPCTR ) {
cp->BIPCTR ++;
}
else {
cp->BIPCTR = 0;
}
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* if DIP replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == DIP)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr, /* for address of replaced block */
int prefetch) /* 1 if the access is a prefetch, 0 if it is not */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
if (prefetch == 0 ) {
cp->misses++;
if (cmd == Read) {
cp->read_misses++;
}
}
/* ECE552 Assignment 4 - BEGIN CODE */
if (strcmp(cp->name, "dl1") == 0) {
for(std::list<evicted_tag>::iterator it = evicted_blks[set].begin(); it != evicted_blks[set].end(); ++it)
{
if(it->tag == tag && it->prefetched) {
//move element to the front of the list
if(it != evicted_blks[set].begin()) {
std::list<evicted_tag>::iterator tmp = it;
evicted_blks[set].splice(evicted_blks[set].begin(), evicted_blks[set], tmp, ++it);
}
cp->prefetch_misses++;
break;
}
}
}
/* ECE552 Assignment 4 - END CODE */
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat, 0);
}
}
/* ECE552 Assignment 4 - BEGIN CODE */
/* evicted cache_blk */
if (strcmp(cp->name, "dl1") == 0) {
if (evicted_blks[set].size() < cp->assoc) {
evicted_blks[set].push_front({false, repl->tag});
} else {
evicted_blks[set].pop_back();
evicted_blks[set].push_front({false, repl->tag});
}
}
/* ECE552 Assignment 4 - END CODE */
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat, prefetch);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
if (prefetch == 0) { /* only regular cache accesses can generate a prefetch */
generate_prefetch(cp, addr);
}
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
if (prefetch == 0) {
cp->hits++;
if (cmd == Read) {
cp->read_hits++;
}
}
/* ECE552 Assignment 4 - BEGIN CODE */
if (blk->prefetched){
if(blk->prefetch_used == 0) {
blk->prefetch_used = 1;
cp->prefetch_useful_cnt++;
}
}
/* ECE552 Assignment 4 - END CODE */
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
if (prefetch == 0) { /* only regular cache accesses can generate a prefetch */
generate_prefetch(cp, addr);
}
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
if (prefetch == 0) {
cp->hits++;
if (cmd == Read) {
cp->read_hits++;
}
}
/* ECE552 Assignment 4 - BEGIN CODE */
if (blk->prefetched){
if(blk->prefetch_used == 0) {
blk->prefetch_used = 1;
cp->prefetch_useful_cnt++;
}
}
/* ECE552 Assignment 4 - END CODE */
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
if (prefetch == 0) { /* only regular cache accesses can generate a prefetch */
generate_prefetch(cp, addr);
}
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* ECE552 Assignment 4 - BEGIN CODE */
void fetch_cache_blk (struct cache_t *cp, md_addr_t addr) {
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
int lat = 0;
struct cache_blk_t *blk, *repl;
//check if the block already exists in cache
if (cp->hsize) {
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex]; blk; blk=blk->hash_next){
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
return;
}
} else {
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head; blk; blk=blk->way_next) {
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
return;
}
}
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* evicted cache_blk */
if (evicted_blks[set].size() < cp->assoc) {
evicted_blks[set].push_front({true, repl->tag});
} else {
evicted_blks[set].pop_back();
evicted_blks[set].push_front({true, repl->tag});
}
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID) {
cp->replacements++;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, 0, 0);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
repl->prefetched = 1;
repl->prefetch_used = 0;
/* read data block */
cp->prefetch_cnt += 1;
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, NULL, 0);
/* update block status */
repl->ready = NULL;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
//tag, set is the address want to access
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
//printf("mother f****r\n");
//sprintf(buf, "%s.inv_rate", name);
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
//the tail of way list is the victim
//move the victim to the head and wait new data block replacing it
//each time when cache misses, new fetched cache block will be placed in MRU position
//cp->sets[set].way_tail still points to victim cache, but the position of victim cache is moved to the head of way list of this set
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
case Pseudo:
{
int bindex=0;
int width_PLRU_state=cp->assoc-1;
int PLRU_state=cp->sets[set].PLRU_STATE;
int width_bindex=0;
for(width_bindex=0;;width_bindex++){
if((cp->assoc>>width_bindex)==1){
break;
}
}
int i=0;
int j=0;
bindex=0;
for(j=0;j<width_bindex;j++){
int bit=(PLRU_state>>i)&0x1;
if(bit==1){
i=i*2+2;
}else if(bit==0){
i=i*2+i;
}
bit=bit^0x1;
bindex=(bindex<<1)|bit;
}
repl=CACHE_BINDEX(cp,cp->sets[set].blks,bindex);
int orig_PLRU_state=cp->sets[set].PLRU_STATE;
cp->sets[set].PLRU_STATE=update_PLRU_state(cp->assoc,bindex,orig_PLRU_state);
}
break;
case MRU:
repl=cp->sets[set].way_head;
update_way_list(&cp->sets[set],repl,Tail);
break;
case LIP:
repl=cp->sets[set].way_tail;
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
cp->last_blk_addr=0;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
//last accessed address
//repl->rag and set form the address of the victim cache block
//cp->last_blk_addr records the address of victim
//
//to use victim cache,
//if l1 cache misses, then victim cache will be scanned
//if victim cache hits, then the victim data block in l1 cache and hit data block in victim cache will excahnge
cp->last_blk_addr=CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
//repl is the block to be replaced
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
//tag is the real address want to access, so use tag to replace repl->tag equalizes replace the victim with desired cache block
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
//if victim cache exists
//read the data block from victim cache first
//and then read data block from lower level cache
//to add victim cache, just need to modify dl1_access_fn function
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}