1 // Copyright 2018 The Emscripten Authors. All rights reserved.
2 // Emscripten is available under two separate licenses, the MIT license and the
3 // University of Illinois/NCSA Open Source License. Both these licenses can be
4 // found in the LICENSE file.
5
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <unistd.h> // for sbrk()
10
11 const int BINS = 32768;
12 const int BIN_MASK = BINS - 1;
13 const int ITERS = 6 * 1024 * 1024;
14 // 12, 64: emmalloc slower
15 // 12, 28: emmalloc much sbrkier and also slower
16 // 256, 512: emmalloc faster without USE_MEMORY
17 const int MIN_SIZE = 16;
18 const int MAX_SIZE = 64;
19 const int SIZE_MASK = 7;
20 const bool POLL_SBRK = false;
21 const bool USE_REALLOC_UP = true;
22 const bool USE_REALLOC_DOWN = true;
23 const bool USE_CALLOC = false;
24 const bool USE_MEMORY = true;
25 const bool USE_SHIFTS = false;
26
randoms()27 void randoms() {
28 srandom(1);
29 size_t before = (size_t)sbrk(0);
30 double sum_sbrk = 0;
31 size_t max_sbrk = before;
32 void* bins[BINS];
33 size_t allocated[BINS];
34 size_t total_allocated = 0;
35 size_t max_allocated = 0;
36 size_t checksum = 0;
37 size_t sizes = 0;
38 size_t allocations = 0;
39 for (int i = 0; i < BINS; i++) {
40 bins[i] = NULL;
41 }
42 for (int i = 0; i < ITERS; i++) {
43 int bin = random() & BIN_MASK;
44 unsigned int r = random();
45 int alloc = r & 1;
46 r >>= 1;
47 int calloc_ = r & 1;
48 r >>= 1;
49 unsigned int size = r & 65535;
50 r >>= 16;
51 int useShifts = r & 1;
52 r >>= 1;
53 unsigned int shifts = r & 15;
54 r >>= 4;
55 if (MAX_SIZE) {
56 size = size % (MAX_SIZE + 1);
57 }
58 if (USE_SHIFTS && useShifts) {
59 size >>= shifts; // spread out values logarithmically
60 }
61 if (SIZE_MASK) size = size & ~SIZE_MASK;
62 if (MIN_SIZE && size < MIN_SIZE) size = MIN_SIZE;
63 if (MAX_SIZE && size > MAX_SIZE) size = MAX_SIZE;
64 //printf("%d\n", size);
65 if (alloc || !bins[bin]) {
66 if (bins[bin]) {
67 bool up = size >= allocated[bin];
68 if ((up && USE_REALLOC_UP) || (!up && USE_REALLOC_DOWN)) {
69 total_allocated -= allocated[bin];
70 bins[bin] = realloc(bins[bin], size);
71 allocated[bin] = size;
72 total_allocated += size;
73 } else {
74 // malloc and free manually
75 free(bins[bin]);
76 bins[bin] = NULL;
77 total_allocated -= allocated[bin];
78 allocated[bin] = 0;
79 bins[bin] = malloc(size);
80 allocated[bin] = size;
81 total_allocated += size;
82 }
83 } else {
84 if (calloc_ && USE_CALLOC) {
85 bins[bin] = malloc(size);
86 allocated[bin] = size;
87 total_allocated += size;
88 } else {
89 bins[bin] = calloc(size, 1);
90 allocated[bin] = size;
91 total_allocated += size;
92 }
93 }
94 if (bins[bin]) {
95 allocations++;
96 sizes += size;
97 }
98 if (USE_MEMORY && bins[bin]) {
99 for (int i = 0; i < size; i++) {
100 ((char*)(bins[bin]))[i] = i;
101 }
102 }
103 } else {
104 if (USE_MEMORY && bins[bin]) {
105 for (int i = 0; i < size; i++) {
106 checksum += ((char*)(bins[bin]))[i];
107 }
108 }
109 free(bins[bin]);
110 bins[bin] = NULL;
111 total_allocated -= allocated[bin];
112 allocated[bin] = 0;
113 }
114 if (total_allocated > max_allocated) {
115 max_allocated = total_allocated;
116 }
117 if (POLL_SBRK) {
118 size_t curr = (size_t)sbrk(0);
119 if (curr > max_sbrk) max_sbrk = curr;
120 sum_sbrk += curr;
121 }
122 }
123 for (int i = 0; i < BINS; i++) {
124 if (bins[i]) {
125 free(bins[i]);
126 total_allocated -= allocated[i];
127 }
128 }
129 size_t after = (size_t)sbrk(0);
130 printf("checksum: %x\n", checksum);
131 printf("allocations: %d\n", allocations);
132 printf("mean alloc size: %.2f\n", double(sizes) / allocations);
133 printf("max allocated: %u\n", max_allocated);
134 double allocs_at_max = max_allocated / (double(sizes) / allocations);
135 printf("allocations #max %.2f\n", allocs_at_max);
136 size_t sbrk_change = after - before;
137 printf("sbrk chng: %u\n", sbrk_change);
138 printf("sbrk chng/allocs: %.2f\n", sbrk_change / double(allocs_at_max));
139 printf("overhead: %.2f\n", -((double(sizes) / allocations) - (sbrk_change / double(allocs_at_max))));
140 printf("sbrk top now: %p\n", (void*)sbrk(0));
141 if (POLL_SBRK) {
142 printf("sbrk mean change: %.2f\n", (sum_sbrk / double(ITERS)) - before);
143 printf("sbrk max change: %u\n", max_sbrk - before);
144 }
145 }
146
main()147 int main() {
148 randoms();
149 }
150
151