/* map function to evenly spread list among ranks, using block allocation */
static int map_spread(mfu_flist flist, uint64_t idx, int ranks, void* args)
{
/* compute global index of this item */
uint64_t offset = mfu_flist_global_offset(flist);
uint64_t global_idx = offset + idx;
/* get global size of the list */
uint64_t global_size = mfu_flist_global_size(flist);
/* get whole number of items on each rank */
uint64_t items_per_rank = global_size / (uint64_t)ranks;
/* if global list size is not divisible by the number of ranks
* then we need to use the remainder */
uint64_t remainder = (global_size) - (items_per_rank * (uint64_t)ranks);
/* If have a remainder, then we give one extra item to
* to each rank starting from rank 0. Compute the number
* of items contained in this set of ranks. There are
* remainder such ranks. */
uint64_t extra = remainder * (items_per_rank + 1);
/* break up into two cases: if you are adding +1 or not
* calculate target rank */
int target_rank;
if (global_idx < extra) {
/* the item falls in the set of ranks that all have an extra item */
target_rank = (int) (global_idx / (items_per_rank + 1));
} else {
/* the item falls into the set of ranks beyond the set holding an extra item */
target_rank = (int) (remainder + (global_idx - extra) / items_per_rank);
}
return target_rank;
}
/* for given depth, evenly spread the files among processes for
* improved load balancing */
static void remove_spread(mfu_flist flist, uint64_t* rmcount)
{
uint64_t idx;
/* initialize our remove count */
*rmcount = 0;
/* get our rank and number of ranks in job */
int rank, ranks;
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &ranks);
/* allocate memory for alltoall exchanges */
size_t bufsize = (size_t)ranks * sizeof(int);
int* sendcounts = (int*) MFU_MALLOC(bufsize);
int* sendsizes = (int*) MFU_MALLOC(bufsize);
int* senddisps = (int*) MFU_MALLOC(bufsize);
int* recvsizes = (int*) MFU_MALLOC(bufsize);
int* recvdisps = (int*) MFU_MALLOC(bufsize);
/* get number of items */
uint64_t my_count = mfu_flist_size(flist);
uint64_t all_count = mfu_flist_global_size(flist);
uint64_t offset = mfu_flist_global_offset(flist);
/* compute number of bytes we'll send */
size_t sendbytes = 0;
for (idx = 0; idx < my_count; idx++) {
const char* name = mfu_flist_file_get_name(flist, idx);
size_t len = strlen(name) + 2;
sendbytes += len;
}
/* compute the number of items that each rank should have */
uint64_t low = all_count / (uint64_t)ranks;
uint64_t extra = all_count - low * (uint64_t)ranks;
/* compute number that we'll send to each rank and initialize sendsizes and offsets */
uint64_t i;
for (i = 0; i < (uint64_t)ranks; i++) {
/* compute starting element id and count for given rank */
uint64_t start, num;
if (i < extra) {
num = low + 1;
start = i * num;
}
else {
num = low;
start = (i - extra) * num + extra * (low + 1);
}
/* compute the number of items we'll send to this task */
uint64_t sendcnt = 0;
if (my_count > 0) {
if (start <= offset && offset < start + num) {
/* this rank overlaps our range,
* and its first element comes at or before our first element */
sendcnt = num - (offset - start);
if (my_count < sendcnt) {
/* the number the rank could receive from us
* is more than we have left */
sendcnt = my_count;
}
}
else if (offset < start && start < offset + my_count) {
/* this rank overlaps our range,
* and our first element comes strictly before its first element */
sendcnt = my_count - (start - offset);
if (num < sendcnt) {
/* the number the rank can receive from us
* is less than we have left */
sendcnt = num;
}
}
}
/* record the number of items we'll send to this task */
sendcounts[i] = (int) sendcnt;
/* set sizes and displacements to 0, we'll fix this later */
sendsizes[i] = 0;
senddisps[i] = 0;
}
/* allocate space */
char* sendbuf = (char*) MFU_MALLOC(sendbytes);
/* copy data into buffer */
int dest = -1;
int disp = 0;
for (idx = 0; idx < my_count; idx++) {
/* get name and type of item */
const char* name = mfu_flist_file_get_name(flist, idx);
mfu_filetype type = mfu_flist_file_get_type(flist, idx);
/* get rank that we're packing data for */
if (dest == -1) {
dest = get_first_nonzero(sendcounts, ranks);
if (dest == -1) {
/* error */
}
/* about to copy first item for this rank,
* record its displacement */
senddisps[dest] = disp;
}
/* identify region to be sent to rank */
char* path = sendbuf + disp;
/* first character encodes item type */
if (type == MFU_TYPE_DIR) {
path[0] = 'd';
}
else if (type == MFU_TYPE_FILE || type == MFU_TYPE_LINK) {
path[0] = 'f';
}
else {
path[0] = 'u';
}
/* now copy in the path */
strcpy(&path[1], name);
/* TODO: check that we don't overflow the int */
/* add bytes to sendsizes and increase displacement */
size_t count = strlen(name) + 2;
sendsizes[dest] += (int) count;
disp += (int) count;
/* decrement the count for this rank */
sendcounts[dest]--;
if (sendcounts[dest] == 0) {
dest = -1;
}
}
/* compute displacements */
senddisps[0] = 0;
for (i = 1; i < (uint64_t)ranks; i++) {
senddisps[i] = senddisps[i - 1] + sendsizes[i - 1];
}
/* alltoall to specify incoming counts */
MPI_Alltoall(sendsizes, 1, MPI_INT, recvsizes, 1, MPI_INT, MPI_COMM_WORLD);
/* compute size of recvbuf and displacements */
size_t recvbytes = 0;
recvdisps[0] = 0;
for (i = 0; i < (uint64_t)ranks; i++) {
recvbytes += (size_t) recvsizes[i];
if (i > 0) {
recvdisps[i] = recvdisps[i - 1] + recvsizes[i - 1];
}
}
/* allocate recvbuf */
char* recvbuf = (char*) MFU_MALLOC(recvbytes);
/* alltoallv to send data */
MPI_Alltoallv(
sendbuf, sendsizes, senddisps, MPI_CHAR,
recvbuf, recvsizes, recvdisps, MPI_CHAR, MPI_COMM_WORLD
);
/* delete data */
char* item = recvbuf;
while (item < recvbuf + recvbytes) {
/* get item name and type */
char type = item[0];
char* name = &item[1];
/* delete item */
remove_type(type, name);
/* keep tally of number of items we deleted */
*rmcount++;
/* go to next item */
size_t item_size = strlen(item) + 1;
item += item_size;
}
/* free memory */
mfu_free(&recvbuf);
mfu_free(&recvdisps);
mfu_free(&recvsizes);
mfu_free(&sendbuf);
mfu_free(&senddisps);
mfu_free(&sendsizes);
mfu_free(&sendcounts);
return;
}
/* given a list of files print from the start to end of the list */
void mfu_flist_print(mfu_flist flist)
{
/* number of items to print from start and end of list */
uint64_t range = 10;
/* allocate send and receive buffers */
size_t pack_size = mfu_flist_file_pack_size(flist);
size_t bufsize = 2 * range * pack_size;
void* sendbuf = MFU_MALLOC(bufsize);
void* recvbuf = MFU_MALLOC(bufsize);
/* get our rank and the size of comm_world */
int rank, ranks;
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &ranks);
/* identify the number of items we have, the total number,
* and our offset in the global list */
uint64_t count = mfu_flist_size(flist);
uint64_t total = mfu_flist_global_size(flist);
uint64_t offset = mfu_flist_global_offset(flist);
/* count the number of items we'll send */
int num = 0;
uint64_t idx = 0;
while (idx < count) {
uint64_t global = offset + idx;
if (global < range || (total - global) <= range) {
num++;
}
idx++;
}
/* allocate arrays to store counts and displacements */
int* counts = (int*) MFU_MALLOC((size_t)ranks * sizeof(int));
int* disps = (int*) MFU_MALLOC((size_t)ranks * sizeof(int));
/* tell rank 0 where the data is coming from */
int bytes = num * (int)pack_size;
MPI_Gather(&bytes, 1, MPI_INT, counts, 1, MPI_INT, 0, MPI_COMM_WORLD);
/* pack items into sendbuf */
idx = 0;
char* ptr = (char*) sendbuf;
while (idx < count) {
uint64_t global = offset + idx;
if (global < range || (total - global) <= range) {
ptr += mfu_flist_file_pack(ptr, flist, idx);
}
idx++;
}
/* compute displacements and total bytes */
int recvbytes = 0;
if (rank == 0) {
int i;
disps[0] = 0;
recvbytes += counts[0];
for (i = 1; i < ranks; i++) {
disps[i] = disps[i - 1] + counts[i - 1];
recvbytes += counts[i];
}
}
/* gather data to rank 0 */
MPI_Gatherv(sendbuf, bytes, MPI_BYTE, recvbuf, counts, disps, MPI_BYTE, 0, MPI_COMM_WORLD);
/* create temporary list to unpack items into */
mfu_flist tmplist = mfu_flist_subset(flist);
/* unpack items into new list */
if (rank == 0) {
ptr = (char*) recvbuf;
char* end = ptr + recvbytes;
while (ptr < end) {
mfu_flist_file_unpack(ptr, tmplist);
ptr += pack_size;
}
}
/* summarize list */
mfu_flist_summarize(tmplist);
/* print files */
if (rank == 0) {
printf("\n");
uint64_t tmpidx = 0;
uint64_t tmpsize = mfu_flist_size(tmplist);
while (tmpidx < tmpsize) {
print_file(tmplist, tmpidx);
tmpidx++;
if (tmpidx == range && total > 2 * range) {
/* going to have to leave some out */
printf("\n<snip>\n\n");
}
}
printf("\n");
}
/* free our temporary list */
mfu_flist_free(&tmplist);
/* free memory */
mfu_free(&disps);
mfu_free(&counts);
mfu_free(&sendbuf);
mfu_free(&recvbuf);
return;
}
