我正在写一个缓存模拟器。这个想法是给一个带有命令的输入文件，跟踪该输入模拟缓存函数的结果，以便我们可以跟踪缓存命中和未命中。我已经编写了以下代码，但似乎无法获得正确的输出。我发布我的整个代码是因为我不想对问题可能出在哪里做出假设。谁能告诉我哪里出错了？
#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <strings.h>
#include "cachelab.h"
/* Always use a 64-bit variable to hold memory addresses*/
typedef unsigned long long int mem_addr_t;
/* a struct that groups cache parameters together */
typedef struct {
int s; /* 2**s cache sets */
int b; /* cacheline block size 2**b bytes */
int E; /* number of cachelines per set */
int S; /* number of sets, derived from S = 2**s */
int B; /* cacheline block size (bytes), derived from B = 2**b */
} cache_param_t;
int verbosity;
/*
* printUsage - Print usage info
*/
void printUsage(char* argv[])
{
printf("Usage: %s [-hv] -s <num> -E <num> -b <num> -t <file>\n", argv[0]);
printf("Options:\n");
printf(" -h Print this help message.\n");
printf(" -v Optional verbose flag.\n");
printf(" -s <num> Number of set index bits.\n");
printf(" -E <num> Number of lines per set.\n");
printf(" -b <num> Number of block offset bits.\n");
printf(" -t <file> Trace file.\n");
printf("\nExamples:\n");
printf(" %s -s 4 -E 1 -b 4 -t traces/yi.trace\n", argv[0]);
printf(" %s -v -s 8 -E 2 -b 4 -t traces/yi.trace\n", argv[0]);
exit(0);
}
int main(int argc, char **argv)
{
cache_param_t par;
bzero(&par, sizeof(par));
char *trace_file;
char c;
while( (c=getopt(argc,argv,"s:E:b:t:vh")) != -1){
switch(c){
case 's':
par.s = atoi(optarg);
break;
case 'E':
par.E = atoi(optarg);
break;
case 'b':
par.b = atoi(optarg);
break;
case 't':
trace_file = optarg;
break;
case 'v':
verbosity = 1;
break;
case 'h':
printUsage(argv);
exit(0);
default:
printUsage(argv);
exit(1);
}
}
if (par.s == 0 || par.E == 0 || par.b == 0 || trace_file == NULL) {
printf("%s: Missing required command line argument\n", argv[0]);
printUsage(argv);
exit(1);
}
/* TODO: Compute S and B based on information passed in */
//Compute S and B, 2^s and 2^b respectively
par.S = (1 << par.s);
par.B = (1 << par.b);
/* TODO: Initialize a cache */
//Structure for a line
typedef struct {
int valid;
mem_addr_t tag;
int timestamp;
} line_st;
//Structure for a set; a pointer to an array of lines
typedef struct {
line_st *lines;
} cache_set;
//Structure for a cache; a pointer to an array of sets
typedef struct {
cache_set *sets;
} cache_t;
//allocate space for sets and for lines
cache_t cache;
cache.sets = malloc(par.S * sizeof(cache_set));
for (int i = 0; i < par.S; i++) {
cache.sets[i].lines = malloc(sizeof(line_st) * par.E);
}
//counters
int hit_count = 0;
int miss_count = 0;
int eviction_count = 0;
/* TODO: Run the trace simulation */
char act; //L,S,M
int size; //size read in from file
int TSTAMP = 0; //value for LRU
int empty = -1; //index of empty space
int H = 0; //is there a hit
int E = 0; //is there an eviction
int toEvict = 0; //keeps track of what to evict
mem_addr_t addr;
//open the file and read it in
FILE * traceFile = fopen(trace_file, "r");
if (traceFile != NULL) {
//keep going while we have additional lines
//while(feof(traceFile) == 0) {
while(fscanf(traceFile, " %c %llx,%d", &act, &addr, &size) == 3){
if (act != 'I') {
//read the next line and look for string formated as " %c %llx,%d"
//sscanf(traceFile, " %c %llx,%d", &act, &addr, &size);
//fscanf(traceFile, " %c %llx,%d", &act, &addr, &size);
//calculate address tag and set index
mem_addr_t addr_tag = addr >> (par.s + par.b);
int tag_size = (64 - (par.s + par.b));
unsigned long long temp = addr << (tag_size);
unsigned long long setid = temp >> (tag_size + par.b);
//unsigned long long setid = ((addr >> par.b) & (par.S - 1));
cache_set set = cache.sets[setid];
int low = par.E + 1;
for(int e = 0; e < par.E; e++) {
if (set.lines[e].valid == 0) {
empty = e;
}
else if (set.lines[e].valid == 1){
if (TSTAMP < low) {
low = TSTAMP;
toEvict = e;
}
if (set.lines[e].tag == addr_tag) {
hit_count++;
H = 1;
set.lines[e].timestamp = TSTAMP;
TSTAMP++;
}
}
}
//if we have a miss
if (H != 1){
miss_count++;
//if we have an empty line
if (empty > -1) {
set.lines[empty].valid = 1;
set.lines[empty].tag = addr_tag;
set.lines[empty].timestamp = TSTAMP;
TSTAMP++;
}
//if the set is full we need to evict
else if (empty < 0) {
E = 1;
set.lines[toEvict].tag = addr_tag;
set.lines[toEvict].timestamp = TSTAMP;
eviction_count++;
}
}
//if the instruction is M, we will always get a hit
if (act == 'M') {
hit_count++;
}
//if the -v flag is set print out all debug information
if (verbosity == 1) {
printf("%c ", act);
//printf("%llx,%d ", addr_tag, setid);
printf("%llx,%d ", addr, size);
if (H == 1) {
printf("Hit ");
}
else if (H != 1) {
printf("Miss ");
}
if (E == 1) {
printf("Eviction ");
}
if (act == 'M') {
printf("Hit ");
}
printf("\n");
}
empty = -1;
H = 0;
E = 0;
}
}
}
/* TODO: Clean up cache resources */
/* TODO: Print out real results */
printSummary(hit_count, miss_count, eviction_count);
return 0;
}
我正在使用以下示例输入运行我的代码:
S 00600aa0,1
S 7ff000384,4
L 7ff000384,4
L 7ff000384,4
L 00600a20,4
L 7ff000384,4
我的代码产生以下结果:
./ -v -s 2 -E 2 -b 3 -t traces/test.trace
S 600aa0,1 Miss
S 7ff000384,4 Miss
L 7ff000384,4 Hit
L 7ff000384,4 Hit
L 600a20,4 Miss Eviction
L 7ff000384,4 Miss Eviction
hits:2 misses:4 evictions:2
但这是它应该产生的:
./ -v -s 2 -E 2 -b 3 -t traces/test.trace
S 600aa0,1 miss
S 7ff000384,4 miss
L 7ff000384,4 hit
L 7ff000384,4 hit
L 600a20,4 miss eviction
L 7ff000384,4 hit
hits:3 misses:3 evictions:1
谁能告诉我哪里做错了？
编辑:
第二个测试文件:
S 00600aa0,1
I 004005b6,5
I 004005bb,5
I 004005c0,5
S 7ff000398,8
I 0040051e,1
S 7ff000390,8
I 0040051f,3
I 00400522,4
S 7ff000378,8
I 00400526,4
S 7ff000370,8
I 0040052a,7
S 7ff000384,4
I 00400531,2
I 00400581,4
L 7ff000384,4
I 00400585,2
I 00400533,7
S 7ff000388,4
I 0040053a,2
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a20,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a60,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a24,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a70,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a28,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a80,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a2c,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a90,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040057d,4
M 7ff000384,4
I 00400581,4
L 7ff000384,4
I 00400585,2
I 00400533,7
S 7ff000388,4
I 0040053a,2
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a30,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a64,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a34,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a74,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a38,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a84,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a3c,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a94,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040057d,4
M 7ff000384,4
I 00400581,4
L 7ff000384,4
I 00400585,2
I 00400533,7
S 7ff000388,4
I 0040053a,2
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a40,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a68,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a44,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a78,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a48,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a88,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a4c,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a98,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040057d,4
M 7ff000384,4
I 00400581,4
L 7ff000384,4
I 00400585,2
I 00400533,7
S 7ff000388,4
I 0040053a,2
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a50,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a6c,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a54,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a7c,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a58,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a8c,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040053c,3
L 7ff000384,4
I 0040053f,2
I 00400541,4
I 00400545,3
I 00400548,4
L 7ff000378,8
I 0040054c,3
L 7ff000388,4
I 0040054f,2
I 00400551,3
L 00600a5c,4
I 00400554,3
S 7ff00038c,4
I 00400557,3
L 7ff000388,4
I 0040055a,2
I 0040055c,4
I 00400560,3
I 00400563,4
L 7ff000370,8
I 00400567,3
L 7ff000384,4
I 0040056a,3
I 0040056d,3
L 7ff00038c,4
I 00400570,3
S 00600a9c,4
I 00400573,4
M 7ff000388,4
I 00400577,4
L 7ff000388,4
I 0040057b,2
I 0040057d,4
M 7ff000384,4
I 00400581,4
L 7ff000384,4
I 00400585,2
I 00400587,1
L 7ff000390,8
I 00400588,1
L 7ff000398,8
I 004005c5,7
L 00600aa0,1
预期值:
My simulator Reference simulator
(s,E,b) Hits Misses Evicts Hits Misses Evicts
(2,2,3) 196 42 34 201 37 29
(2,4,3) 208 30 14 212 26 10
最佳答案
那里有棘手的错误。我将中间的 for 循环更改为仅设置 empty 如果它已经是 -1，因此它将使用找到的第一个空点，然后一旦找到一个就不会再更改它空位。我还将 low 的初始化修改为 INT_MAX，并通过更改相关的 else 条件来查找最近最少使用的真实值。我还重新排序代码以在寻找逐出候选者之前寻找匹配项，因为找到匹配项会刷新缓存时间戳。您还忘记了在 Miss Eviction 的情况下增加 TSTAMP。
#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <strings.h>
#include <limits.h>
//#include "cachelab.h"
/* Always use a 64-bit variable to hold memory addresses*/
typedef unsigned long long int mem_addr_t;
/* a struct that groups cache parameters together */
typedef struct
{
int s; /* 2**s cache sets */
int b; /* cacheline block size 2**b bytes */
int E; /* number of cachelines per set */
int S; /* number of sets, derived from S = 2**s */
int B; /* cacheline block size (bytes), derived from B = 2**b */
} cache_param_t;
int verbosity;
/* printUsage - Print usage info */
void printUsage( char *argv[] )
{
printf( "Usage: %s [-hv] -s <num> -E <num> -b <num> -t <file>\n", argv[0] );
printf( "Options:\n" );
printf( " -h Print this help message.\n" );
printf( " -v Optional verbose flag.\n" );
printf( " -s <num> Number of set index bits.\n" );
printf( " -E <num> Number of lines per set.\n" );
printf( " -b <num> Number of block offset bits.\n" );
printf( " -t <file> Trace file.\n" );
printf( "\nExamples:\n" );
printf( " %s -s 4 -E 1 -b 4 -t traces/yi.trace\n", argv[0] );
printf( " %s -v -s 8 -E 2 -b 4 -t traces/yi.trace\n", argv[0] );
exit( 0 );
}
void printSummary( int hit_count, int miss_count, int eviction_count )
{
printf( "hits: %d misses: %d evictions: %d\n", hit_count, miss_count, eviction_count );
}
int main( int argc, char **argv )
{
cache_param_t par;
bzero( &par, sizeof ( par ) );
char *trace_file;
char c;
while ( ( c = getopt( argc, argv, "s:E:b:t:vh" ) ) != -1 )
{
switch ( c )
{
case 's':
par.s = atoi( optarg );
break;
case 'E':
par.E = atoi( optarg );
break;
case 'b':
par.b = atoi( optarg );
break;
case 't':
trace_file = optarg;
break;
case 'v':
verbosity = 1;
break;
case 'h':
printUsage( argv );
exit( 0 );
default:
printUsage( argv );
exit( 1 );
}
}
if ( par.s == 0 || par.E == 0 || par.b == 0 || trace_file == NULL )
{
printf( "%s: Missing required command line argument\n", argv[0] );
printUsage( argv );
exit( 1 );
}
/* TODO: Compute S and B based on information passed in */
//Compute S and B, 2^s and 2^b respectively
par.S = ( 1 << par.s );
par.B = ( 1 << par.b );
/* TODO: Initialize a cache */
//Structure for a line
typedef struct
{
int valid;
mem_addr_t tag;
int timestamp;
} line_st;
//Structure for a set; a pointer to an array of lines
typedef struct
{
line_st *lines;
} cache_set;
//Structure for a cache; a pointer to an array of sets
typedef struct
{
cache_set *sets;
} cache_t;
//allocate space for sets and for lines
cache_t cache;
cache.sets = malloc( par.S * sizeof ( cache_set ) );
for ( int i = 0; i < par.S; i++ )
{
cache.sets[i].lines = malloc( sizeof ( line_st ) * par.E );
}
//counters
int hit_count = 0;
int miss_count = 0;
int eviction_count = 0;
/* TODO: Run the trace simulation */
char act; //L,S,M
int size; //size read in from file
int TSTAMP = 0; //value for LRU
int empty = -1; //index of empty space
int H = 0; //is there a hit
int E = 0; //is there an eviction
mem_addr_t addr;
//open the file and read it in
FILE *traceFile = fopen( trace_file, "r" );
if ( traceFile != NULL )
{
while ( fscanf( traceFile, " %c %llx,%d", &act, &addr, &size ) == 3 )
{
int toEvict = 0; //keeps track of what to evict
if ( act != 'I' )
{
//calculate address tag and set index
mem_addr_t addr_tag = addr >> ( par.s + par.b );
int tag_size = ( 64 - ( par.s + par.b ) );
unsigned long long temp = addr << ( tag_size );
unsigned long long setid = temp >> ( tag_size + par.b );
cache_set set = cache.sets[setid];
int low = INT_MAX; // CHANGED, also added #include <limits.h>
for ( int e = 0; e < par.E; e++ ) {
if ( set.lines[e].valid == 1 ) {
// CHANGED ORDER: look for hit before eviction candidates
if ( set.lines[e].tag == addr_tag ) {
hit_count++;
H = 1;
set.lines[e].timestamp = TSTAMP;
TSTAMP++;
}
// CHANGED WHOLE ELSE: look for oldest for eviction.
else if ( set.lines[e].timestamp < low ) {
low = set.lines[e].timestamp;
toEvict = e;
}
}
// CHANGED: if we haven't yet found an empty, mark one that we found.
else if( empty == -1 ) {
empty = e;
}
}
//if we have a miss
if ( H != 1 )
{
miss_count++;
//if we have an empty line
if ( empty > -1 )
{
set.lines[empty].valid = 1;
set.lines[empty].tag = addr_tag;
set.lines[empty].timestamp = TSTAMP;
TSTAMP++;
}
//if the set is full we need to evict
else if ( empty < 0 )
{
E = 1;
set.lines[toEvict].tag = addr_tag;
set.lines[toEvict].timestamp = TSTAMP;
TSTAMP++; // CHANGED: increment TSTAMP here too
eviction_count++;
}
}
//if the instruction is M, we will always get a hit
if ( act == 'M' )
{
hit_count++;
}
//if the -v flag is set print out all debug information
if ( verbosity == 1 )
{
printf( "%c ", act );
printf( "%llx,%d", addr, size );
if ( H == 1 )
{
printf( "Hit " );
}
else if ( H != 1 )
{
printf( "Miss " );
}
if ( E == 1 )
{
printf( "Eviction " );
}
// CHANGED: don't print Hit again since 'M' is always going to print Hit above.
printf( "\n" );
}
empty = -1;
H = 0;
E = 0;
}
}
}
/* TODO: Clean up cache resources */
/* TODO: Print out real results */
printSummary( hit_count, miss_count, eviction_count );
return 0;
}
我的结果:
$ ./ca2 -s 2 -E 2 -b 3 -t f2.trace
hits: 201 misses: 37 evictions: 29
$ ./ca2 -s 2 -E 4 -b 3 -t f2.trace
hits: 212 misses: 26 evictions: 10
关于缓存模拟器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23092307/