void Misc::reverseStack(stack<int> &s) {
if (s.size()<=1) return;
int x = s.top();
s.pop();
reverseStack(s);
pushBottom(s, x);
}
void pushBottom(stack<int> &s, int x) {
if (s.empty()) {
s.push(x);
return;
}
int top = s.top();
s.pop();
pushBottom(s, x);
s.push(top);
}
void * owner(void * arg)
{
int i;
for(i=0; i<ROUNDS; ++i)
{
if(nondet())
{
popBottom();
}
else
{
pushBottom();
}
}
}
Deque* parseFile(char* fName)
{
FILE* f = fopen(fName, "r");
if (f == NULL) {
perror("Cannot open file\n");
}
Deque* d = getDeque();
char line[255];
while (fgets(line, 255, f) != NULL) {
pushBottom(d, atoi(line)); // assuming all input is valid...
}
return d;
}
int main(int argc, char** argv)
{
if (argc != 4) {
printf("Incorrect number of arguments.\n"
"1: Number of frames\n"
"2: traces file name\n"
"3: LRU or LFU\n");
}
int nFrames = atoi(argv[1]);
char* fName = argv[2];
char* opt = argv[3];
const unsigned int pageTableSize = 1024;
bool mode = 0;
int numFaults = 0;
int numUsedFrames = 0;
int tlbMisses = 0;
int tlbCount = 0;
if (strcmp(opt, "LRU") == 0 || strcmp(opt, "LFU") == 0) {
mode = strcmp(opt, "LRU") == 0 ? LRU : LFU;
} else {
printf("Wrong input. Need LRU or LFU.\n");
exit(EXIT_FAILURE);
}
Deque* traces = parseFile(fName); // read in page table
Deque* lru = getDeque(); // most recent on top, oldest on bottom
// initialize transitive lookaside buffer
TlbInfoEntry* tlb = (TlbInfoEntry*)malloc(sizeof(TlbInfoEntry) * TLB_SIZE);
for (int i = 0; i < TLB_SIZE; i++) {
tlb[i].frameNum = -1;
tlb[i].hitCount = 0;
tlb[i].pageNum = -1;
}
// initialize page table
PageInfoEntry* pageTable = (PageInfoEntry*) malloc(sizeof(PageInfoEntry) * pageTableSize);
for (int i = 0; i < pageTableSize; i++) {
pageTable[i].frameNumber = 0;
pageTable[i].numReferences = 0;
pageTable[i].valid = false;
}
while (traces->size > 0) {
int pageIndex = popTop(traces); // get next trace
pageTable[pageIndex].numReferences++; // page is referenced, add to count (for LFU), not LRU
if (pageTable[pageIndex].valid) { // if page is valid, remove it
// simulate parallel TLB lookup of page #. (Serial lookup must be done for simulation)
bool inTlb = false;
for (int i = 0; i < TLB_SIZE; i++) {
if (tlb[i].pageNum == pageIndex) {
int frameNum = tlb[i].frameNum;
/*
Code that uses actual physical frame memory
*/
tlb[i].hitCount++;
inTlb = true;
}
}
if (!inTlb) {
tlbMisses++;
// add missed item to tlb;
if (tlbCount < TLB_SIZE) {
tlb[tlbCount].pageNum = pageIndex;
tlb[tlbCount].frameNum = pageTable[pageIndex].frameNumber;
} else {
// find the least recently used page #, and replace it
int minHitCount = INT_MAX, minHitIndex = 0;
for (int i = 0; i < TLB_SIZE; i++) {
if (tlb[i].hitCount < minHitCount) {
minHitCount = tlb[i].hitCount;
minHitIndex = i;
}
}
tlb[minHitIndex].pageNum = pageIndex;
tlb[minHitIndex].frameNum = pageTable[pageIndex].frameNumber;
}
// if the page# was not found in the TLB, use page table instead
if (mode == LRU) { // and place back at bottom of Deque
removeItem(lru, pageIndex);
pushTop(lru, pageIndex);
}
}
} else {
numFaults++; // item not valid -> numFaults++
int frameId = 0;
if (numUsedFrames < nFrames) {
frameId = numUsedFrames++;
pushBottom(lru, frameId); // push to bottom of lru stack
} else {
switch (mode) {
case LRU:
{// find least recently used item --> i.e. top of lru stack.
int topFrameId = popTop(lru); // remove top item in lru stack
frameId = pageTable[topFrameId].frameNumber; // get the frame id
pageTable[topFrameId].valid = false; // mark old frame index as invalid
pushBottom(lru, topFrameId); // push the new frame id to bottom of lru stack
break;
}
case LFU: // opposite of LRU --> find items which have been used the least
{
// find items with min. references (closest to 0)
// Grab first valid frame with 0 references, or minimum otherwise
int minIndex = 0;
int minRefs = INT_MAX;
for (int i = 0; i < pageTableSize; i++) {
if (pageTable[i].valid) {
if (pageTable[i].numReferences == 0) {
minIndex = i;
break;
}
if (pageTable[i].numReferences < minRefs) {
minRefs = pageTable[i].numReferences;
minIndex = i;
}
}
}
pageTable[minIndex].valid = false; // Since used, make invalid
frameId = pageTable[minIndex].frameNumber; // update new frame number (frameId)
break;
}
default:
break;
}
}
pageTable[pageIndex].frameNumber = frameId; // update frame, and reset staistics
pageTable[pageIndex].numReferences = 0;
pageTable[pageIndex].valid = true;
}
}
freeDeque(lru); // free all allocated memory
freeDeque(traces);
free(pageTable);
printf("The number of Page Faults was: %d\n"
"The number of TLB misses was: %d\n", numFaults, tlbMisses);
//getchar();
return EXIT_SUCCESS;
}
