standalone_malloc_test.cc revision 09575a176caef64cf43f3eac8e197ee4f55572bd 
1#include <stdio.h>
2#include <vector>
3#include <pthread.h>
4#include <malloc.h>
5#include <algorithm>
6
7using namespace std;
8
9const size_t kNumThreds = 16;
10const size_t kNumIters = 1 << 23;
11
12static void *MallocThread(void *t) {
13  size_t total_malloced = 0, total_freed = 0;
14  size_t max_in_use = 0;
15  size_t tid = reinterpret_cast<size_t>(t);
16  vector<pair<char *, size_t> > allocated;
17  allocated.reserve(kNumIters);
18  for (size_t i = 1; i < kNumIters; i++) {
19    if ((i % (kNumIters / 4)) == 0 && tid == 0)
20      fprintf(stderr, "   T[%ld] iter %ld\n", tid, i);
21    bool allocate = (i % 5) <= 2;  // 60% malloc, 40% free
22    if (i > kNumIters / 4)
23      allocate = i % 2;  // then switch to 50% malloc, 50% free
24    if (allocate) {
25      size_t size = 1 + (i % 200);
26      if ((i % 10001) == 0)
27        size *= 4096;
28      total_malloced += size;
29      char *x = new char[size];
30      x[0] = x[size - 1] = x[size / 2] = 0;
31      allocated.push_back(make_pair(x, size));
32      max_in_use = max(max_in_use, total_malloced - total_freed);
33    } else {
34      if (allocated.empty()) continue;
35      size_t slot = i % allocated.size();
36      char *p = allocated[slot].first;
37      p[0] = 0;  // emulate last user touch of the block
38      size_t size = allocated[slot].second;
39      total_freed += size;
40      swap(allocated[slot], allocated.back());
41      allocated.pop_back();
42      delete [] p;
43    }
44  }
45  if (tid == 0)
46    fprintf(stderr, "   T[%ld] total_malloced: %ldM in use %ldM max %ldM\n",
47           tid, total_malloced >> 20, (total_malloced - total_freed) >> 20,
48           max_in_use >> 20);
49  for (size_t i = 0; i < allocated.size(); i++)
50    delete [] allocated[i].first;
51  return 0;
52}
53
54// Build with -Dstandalone_malloc_test=main to make it a separate program.
55int standalone_malloc_test() {
56  pthread_t t[kNumThreds];
57  for (size_t i = 0; i < kNumThreds; i++)
58    pthread_create(&t[i], 0, MallocThread, reinterpret_cast<void *>(i));
59  for (size_t i = 0; i < kNumThreds; i++)
60    pthread_join(t[i], 0);
61  malloc_stats();
62  return 0;
63}
64