88 lines · cpp
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 12inline void break_optimization(void *arg) {13 __asm__ __volatile__("" : : "r" (arg) : "memory");14}15 16__attribute__((noinline))17static void *MallocThread(void *t) {18 size_t total_malloced = 0, total_freed = 0;19 size_t max_in_use = 0;20 size_t tid = reinterpret_cast<size_t>(t);21 vector<pair<char *, size_t> > allocated;22 allocated.reserve(kNumIters);23 for (size_t i = 1; i < kNumIters; i++) {24 if ((i % (kNumIters / 4)) == 0 && tid == 0)25 fprintf(stderr, " T[%ld] iter %ld\n", tid, i);26 bool allocate = (i % 5) <= 2; // 60% malloc, 40% free27 if (i > kNumIters / 4)28 allocate = i % 2; // then switch to 50% malloc, 50% free29 if (allocate) {30 size_t size = 1 + (i % 200);31 if ((i % 10001) == 0)32 size *= 4096;33 total_malloced += size;34 char *x = new char[size];35 x[0] = x[size - 1] = x[size / 2] = 0;36 allocated.push_back(make_pair(x, size));37 max_in_use = max(max_in_use, total_malloced - total_freed);38 } else {39 if (allocated.empty()) continue;40 size_t slot = i % allocated.size();41 char *p = allocated[slot].first;42 p[0] = 0; // emulate last user touch of the block43 size_t size = allocated[slot].second;44 total_freed += size;45 swap(allocated[slot], allocated.back());46 allocated.pop_back();47 delete [] p;48 }49 }50 if (tid == 0)51 fprintf(stderr, " T[%ld] total_malloced: %ldM in use %ldM max %ldM\n",52 tid, total_malloced >> 20, (total_malloced - total_freed) >> 20,53 max_in_use >> 20);54 for (size_t i = 0; i < allocated.size(); i++)55 delete [] allocated[i].first;56 return 0;57}58 59template <int depth>60struct DeepStack {61 __attribute__((noinline))62 static void *run(void *t) {63 break_optimization(0);64 DeepStack<depth - 1>::run(t);65 break_optimization(0);66 return 0;67 }68};69 70template<>71struct DeepStack<0> {72 static void *run(void *t) {73 MallocThread(t);74 return 0;75 }76};77 78// Build with -Dstandalone_malloc_test=main to make it a separate program.79int standalone_malloc_test() {80 pthread_t t[kNumThreds];81 for (size_t i = 0; i < kNumThreds; i++)82 pthread_create(&t[i], 0, DeepStack<200>::run, reinterpret_cast<void *>(i));83 for (size_t i = 0; i < kNumThreds; i++)84 pthread_join(t[i], 0);85 malloc_stats();86 return 0;87}88