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mezum/AppDelegate-timeResolution.cpp

Last active December 17, 2015 07:41
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cocos2d-x (3.8) を用いて steady_clock の精度を調査した時に用いたコード及びその結果
Raw
AppDelegate-timeResolution.cpp
AppDelegate::AppDelegate()
{
std::thread th{[]{
using clock = std::chrono::steady_clock;
constexpr int64_t LOOP_COUNT = 100000;
constexpr int64_t DIST_FREQ = 200;
constexpr int64_t DIST_SIZE = 16;
std::this_thread::sleep_for(std::chrono::seconds{10});
int64_t min = std::numeric_limits<int64_t>::max();
int64_t total = 0;
int64_t max = std::numeric_limits<int64_t>::min();
float total2 = 0;
std::array<int, DIST_SIZE> dist{0};
int overCount = 0;
for (int i = 0; i < LOOP_COUNT; i++) {
auto a = clock::now();
auto b = clock::now();
auto diff = std::chrono::duration_cast<std::chrono::nanoseconds>(b - a).count();
if (diff < DIST_FREQ * DIST_SIZE) {
dist[diff / DIST_FREQ]++;
}
else {
overCount++;
}
total += diff;
total2 += diff * diff;
if (diff < min) min = diff;
if (diff > max) max = diff;
}
float mean = (float)total / LOOP_COUNT;
float sd = std::sqrt(total2 / LOOP_COUNT - mean * mean);
CCLOG("min:%lldns, max:%lldns, mean:%f.2ns, sd:%f.2ns", min, max, mean, sd);
for (int i = 0; i < DIST_SIZE; i++) {
CCLOG("%5lld - %5lld : %d", DIST_FREQ * i, DIST_FREQ * (i + 1) - 1, dist[i]);
}
CCLOG(" %5lld+: %d", DIST_FREQ * DIST_SIZE, overCount);
}};
th.detach();
}
Raw
log_205SH_Android4.1.log
// 出現値の関係で DIST_FREQ = 3000 に設定
min:0ns, max:7294369ns, mean:1606.592041.2ns, sd:44291.617188.2ns
0 - 2999 : 96193
3000 - 5999 : 0
6000 - 8999 : 0
9000 - 11999 : 0
12000 - 14999 : 0
15000 - 17999 : 0
18000 - 20999 : 0
21000 - 23999 : 0
24000 - 26999 : 0
27000 - 29999 : 0
30000 - 32999 : 3784
33000 - 35999 : 0
36000 - 38999 : 0
39000 - 41999 : 0
42000 - 44999 : 0
45000 - 47999 : 0
48000+: 23
Raw
log_GalaxySIILTE_CyanogenMod12.log
// 出現値の関係で DIST_FREQ = 3000 に設定
min:0ns, max:3417969ns, mean:973.510742.2ns, sd:21201.652344.2ns
0 - 2999 : 97488
3000 - 5999 : 0
6000 - 8999 : 0
9000 - 11999 : 0
12000 - 14999 : 0
15000 - 17999 : 0
18000 - 20999 : 0
21000 - 23999 : 0
24000 - 26999 : 0
27000 - 29999 : 0
30000 - 32999 : 2481
33000 - 35999 : 0
36000 - 38999 : 0
39000 - 41999 : 0
42000 - 44999 : 0
45000 - 47999 : 0
48000+: 31
Raw
log_HTC-J_Android4.0.log
// 出現値の関係で DIST_FREQ = 3000 に設定
min:0ns, max:11597742ns, mean:2880.207275.2ns, sd:63398.468750.2ns
0 - 2999 : 92378
3000 - 5999 : 0
6000 - 8999 : 0
9000 - 11999 : 0
12000 - 14999 : 0
15000 - 17999 : 0
18000 - 20999 : 0
21000 - 23999 : 0
24000 - 26999 : 0
27000 - 29999 : 0
30000 - 32999 : 7586
33000 - 35999 : 0
36000 - 38999 : 0
39000 - 41999 : 0
42000 - 44999 : 0
45000 - 47999 : 0
48000+: 36
Raw
log_iPadAir_iOS7.0.log
// 出現値の関係で DIST_FREQ = 20 に設定
min:125ns, max:89875ns, mean:131.350372.2ns, sd:405.521515.2ns
0 - 19 : 0
20 - 39 : 0
40 - 59 : 0
60 - 79 : 0
80 - 99 : 0
100 - 119 : 0
120 - 139 : 92625
140 - 159 : 0
160 - 179 : 7334
180 - 199 : 0
200 - 219 : 10
220 - 239 : 0
240 - 259 : 1
260 - 279 : 0
280 - 299 : 1
300 - 319 : 0
320+: 29
Raw
log_iPhone5_iOS7.0.log
min:416ns, max:531167ns, mean:530.464050.2ns, sd:2514.324951.2ns
0 - 199 : 0
200 - 399 : 0
400 - 599 : 98642
600 - 799 : 9
800 - 999 : 786
1000 - 1199 : 512
1200 - 1399 : 1
1400 - 1599 : 4
1600 - 1799 : 1
1800 - 1999 : 0
2000 - 2199 : 1
2200 - 2399 : 2
2400 - 2599 : 0
2600 - 2799 : 0
2800 - 2999 : 1
3000 - 3199 : 0
3200+: 41
Raw
log_iPodTouch4Gen_iOS6.1.log
min:1916ns, max:21347875ns, mean:5236.863770.2ns, sd:177577.484375.2ns
0 - 199 : 0
200 - 399 : 0
400 - 599 : 0
600 - 799 : 0
800 - 999 : 0
1000 - 1199 : 0
1200 - 1399 : 0
1400 - 1599 : 0
1600 - 1799 : 0
1800 - 1999 : 49840
2000 - 2199 : 18621
2200 - 2399 : 31256
2400 - 2599 : 20
2600 - 2799 : 1
2800 - 2999 : 5
3000 - 3199 : 6
3200+: 251
Raw
log_iPodTouch5Gen_iOS7.0.log
min:1666ns, max:2033417ns, mean:1856.185547.2ns, sd:12585.189453.2ns
0 - 199 : 0
200 - 399 : 0
400 - 599 : 0
600 - 799 : 0
800 - 999 : 0
1000 - 1199 : 0
1200 - 1399 : 0
1400 - 1599 : 0
1600 - 1799 : 95452
1800 - 1999 : 1640
2000 - 2199 : 1725
2200 - 2399 : 972
2400 - 2599 : 89
2600 - 2799 : 8
2800 - 2999 : 2
3000 - 3199 : 1
3200+: 111
Raw
log_N-04D_Android4.0.log
min:740ns, max:5045037ns, mean:1054.027100.2ns, sd:33417.429688.2ns
0 - 199 : 0
200 - 399 : 0
400 - 599 : 0
600 - 799 : 67411
800 - 999 : 32180
1000 - 1199 : 95
1200 - 1399 : 23
1400 - 1599 : 28
1600 - 1799 : 45
1800 - 1999 : 13
2000 - 2199 : 11
2200 - 2399 : 15
2400 - 2599 : 9
2600 - 2799 : 13
2800 - 2999 : 31
3000 - 3199 : 5
3200+: 121
Raw
log_RAZR-M_Android4.1.log
// 出現値の関係で DIST_FREQ = 3000 に設定
min:0ns, max:8209980ns, mean:1082.862671.2ns, sd:36522.488281.2ns
0 - 2999 : 97574
3000 - 5999 : 0
6000 - 8999 : 0
9000 - 11999 : 0
12000 - 14999 : 0
15000 - 17999 : 0
18000 - 20999 : 0
21000 - 23999 : 0
24000 - 26999 : 0
27000 - 29999 : 0
30000 - 32999 : 2387
33000 - 35999 : 0
36000 - 38999 : 0
39000 - 41999 : 0
42000 - 44999 : 0
45000 - 47999 : 0
48000+: 39
Raw
log_T-01D_Android4.0.log
// 出現値の関係で DIST_FREQ = 3000 に設定
min:0ns, max:793457ns, mean:961.914062.2ns, sd:6403.461426.2ns
0 - 2999 : 96957
3000 - 5999 : 0
6000 - 8999 : 0
9000 - 11999 : 0
12000 - 14999 : 0
15000 - 17999 : 0
18000 - 20999 : 0
21000 - 23999 : 0
24000 - 26999 : 0
27000 - 29999 : 0
30000 - 32999 : 3022
33000 - 35999 : 0
36000 - 38999 : 0
39000 - 41999 : 0
42000 - 44999 : 0
45000 - 47999 : 0
48000+: 21
Raw
log_XperiaZ1f_Android4.4.log
min:364ns, max:1083177ns, mean:519.057007.2ns, sd:5515.062988.2ns
0 - 199 : 0
200 - 399 : 438
400 - 599 : 91801
600 - 799 : 7024
800 - 999 : 622
1000 - 1199 : 41
1200 - 1399 : 2
1400 - 1599 : 0
1600 - 1799 : 1
1800 - 1999 : 1
2000 - 2199 : 0
2200 - 2399 : 1
2400 - 2599 : 0
2600 - 2799 : 0
2800 - 2999 : 0
3000 - 3199 : 0
3200+: 69
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