static void run_benchmark(char *name, void (*benchmark)(void *),
void (*setup)(void *), void (*teardown)(void *),
void *data, int count, int iter) {
int i;
double min = HUGE_VAL;
double sum = 0.0;
double max = 0.0;
for (i = 0; i < count; i++) {
double begin, total;
if (setup != NULL) {
setup(data);
}
begin = gettimedouble();
benchmark(data);
total = gettimedouble() - begin;
if (teardown != NULL) {
teardown(data);
}
if (total < min) {
min = total;
}
if (total > max) {
max = total;
}
sum += total;
}
printf("%s: min ", name);
print_number(min * 1000000000.0 / iter);
printf("ns / avg ");
print_number((sum / count) * 1000000000.0 / iter);
printf("ns / max ");
print_number(max * 1000000000.0 / iter);
printf("ns\n");
}
bool benchmark::State::KeepRunning()
{
if (count & countMask) {
++count;
return true;
}
double now;
uint64_t nowCycles;
if (count == 0) {
lastTime = beginTime = now = gettimedouble();
lastCycles = beginCycles = nowCycles = perf_cpucycles();
}
else {
now = gettimedouble();
double elapsed = now - lastTime;
double elapsedOne = elapsed * countMaskInv;
if (elapsedOne < minTime) minTime = elapsedOne;
if (elapsedOne > maxTime) maxTime = elapsedOne;
// We only use relative values, so don't have to handle 64-bit wrap-around specially
nowCycles = perf_cpucycles();
uint64_t elapsedOneCycles = (nowCycles - lastCycles) * countMaskInv;
if (elapsedOneCycles < minCycles) minCycles = elapsedOneCycles;
if (elapsedOneCycles > maxCycles) maxCycles = elapsedOneCycles;
if (elapsed*128 < maxElapsed) {
// If the execution was much too fast (1/128th of maxElapsed), increase the count mask by 8x and restart timing.
// The restart avoids including the overhead of this code in the measurement.
countMask = ((countMask<<3)|7) & ((1LL<<60)-1);
countMaskInv = 1./(countMask+1);
count = 0;
minTime = std::numeric_limits<double>::max();
maxTime = std::numeric_limits<double>::min();
minCycles = std::numeric_limits<uint64_t>::max();
maxCycles = std::numeric_limits<uint64_t>::min();
return true;
}
if (elapsed*16 < maxElapsed) {
uint64_t newCountMask = ((countMask<<1)|1) & ((1LL<<60)-1);
if ((count & newCountMask)==0) {
countMask = newCountMask;
countMaskInv = 1./(countMask+1);
}
}
}
lastTime = now;
lastCycles = nowCycles;
++count;
if (now - beginTime < maxElapsed) return true; // Keep going
--count;
assert(count != 0 && "count == 0 => (now == 0 && beginTime == 0) => return above");
// Output results
double average = (now-beginTime)/count;
int64_t averageCycles = (nowCycles-beginCycles)/count;
std::cout << std::fixed << std::setprecision(15) << name << "," << count << "," << minTime << "," << maxTime << "," << average << ","
<< minCycles << "," << maxCycles << "," << averageCycles << "\n";
return false;
}
