int BufferManager::findKey(int key) {
int checked[4] = {0, 0, 0, 0};
// Look for key in pages in memory
for (int i = 0; i < 2; i++) {
int pageNum = pageNums[i];
checked[pageNum - 1] = 1;
if (pages[i].findKey(key) != -1) { return i; }
}
// Look for key in pages on disk
for (int i = 0; i < 4; i++) {
if (checked[i] == 0) {
int pageNum = i + 1;
int index = selectVictim();
pageOut(index);
pageIn(index, pageNum);
if (pages[index].findKey(key) != -1) { return index; }
}
}
return -1;
}
main(int argc, char *argv[])
{
char *tracename;
int page_number,frame_no, done ;
int do_line;
int no_events, disk_writes, disk_reads;
int debugmode;
enum repl replace;
int allocated=0, modified=0;
int victim_page;
unsigned address;
char rw;
int i;
page victim;
FILE *trace;
if (argc < 5) {
printf( "Usage: ./memsim inputfile numberframes replacementmode debugmode \n");
exit ( -1);
}
else {
tracename = argv[1];
trace = fopen( tracename, "r");
if (trace == NULL ) {
printf( "Cannot open trace file %s \n", tracename);
exit ( -1);
}
numFrames = atoi(argv[2]);
if (numFrames < 1) {
printf( "Frame number must be at least 1\n");
exit ( -1);
}
if (strcmp(argv[3], "lru\0") == 0)
replace = lru;
else if (strcmp(argv[3], "rand\0") == 0)
replace = random;
else if (strcmp(argv[3], "esc\0") == 0)
replace = enhanced2ndchance;
else
{
printf( "Replacement algorithm must be rand/lru/esc \n");
exit ( -1);
}
if (strcmp(argv[4], "quiet\0") == 0)
debugmode = 0;
else if (strcmp(argv[4], "debug\0") == 0)
debugmode = 1;
else
{
printf( "Replacement algorithm must be quiet/debug \n");
exit ( -1);
}
}
done = createMMU (numFrames);
if ( done == -1 ) {
printf( "Cannot create MMU" ) ;
exit(-1);
}
no_events = 0 ;
disk_writes = 0 ;
disk_reads = 0 ;
do_line = fscanf(trace,"%x %c",&address,&rw);
while (do_line == 2) {
page_number = address >> pageoffset;
frame_no = checkInMemory( page_number) ; /* ask for physical address */
if ( frame_no == -1 )
{
disk_reads++ ; /* Page fault, need to load it into memory */
if (debugmode)
printf( "Page fault %8d \n", page_number) ;
if (allocated < numFrames) /* allocate it to an empty frame */
{
allocateFrame(page_number);
allocated++;
}
else{
victim = selectVictim(page_number, replace) ; /* find frameNo of the victim */
if (victim.modified) /* need to know victim page and modified */
{
disk_writes++;
if (debugmode) printf( "Disk write %8d \n", victim.pageNo) ;
}
else
if (debugmode) printf( "Discard %8d \n", victim.pageNo) ;
}
}
if ( rw == 'R')
/* need to update reference status for lru or esc */
if (debugmode) printf( "reading %8d \n", page_number) ;
else if ( rw == 'W')
/* need to set this page as modified */
if (debugmode) printf( "writting %8d \n", page_number) ;
else {
printf( "Badly formatted file. Error on line %d\n", no_events+1);
exit (-1);
}
no_events++;
do_line = fscanf(trace,"%x %c",&address,&rw);
}
printf( "total memory frames: %d\n", numFrames);
printf( "events in trace: %d\n", no_events);
printf( "total disk reads: %d\n", disk_reads);
printf( "total disk writes: %d\n", disk_writes);
printf( "page fault rate: %.2f\n", (float) disk_reads/no_events);
}
void Human_Guard::check()
{
selectVictim();
AbstractAI::check();
}