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缓存模拟器

转载 作者：行者123 更新时间：2023-12-04 11:40:34 24 4
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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/

24 4 0
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