Handle the case where gettimeofday() goes backwards or returns the same value

twice; it could cause division by zero in the unit test framework.
(We already had one fix for this in place, but it was incomplete.)

This could in theory happen on any system, since there are few guarantees
about gettimeofday(), but seems to only happen in practice on GNU/Hurd, where
gettimeofday() is cached and only updated ever so often.

R=sanjay


git-svn-id: https://snappy.googlecode.com/svn/trunk@65 03e5f5b5-db94-4691-08a0-1a8bf15f6143
This commit is contained in:
snappy.mirrorbot@gmail.com 2012-07-04 09:34:48 +00:00
parent 3ec60ac987
commit e89f20ab46
1 changed files with 19 additions and 14 deletions

View File

@ -204,27 +204,32 @@ void Benchmark::Run() {
benchmark_runs[run].cpu_time_us = benchmark_cpu_time_us;
}
string heading = StringPrintf("%s/%d", name_.c_str(), test_case_num);
string human_readable_speed;
nth_element(benchmark_runs,
benchmark_runs + kMedianPos,
benchmark_runs + kNumRuns,
BenchmarkCompareCPUTime());
int64 real_time_us = benchmark_runs[kMedianPos].real_time_us;
int64 cpu_time_us = benchmark_runs[kMedianPos].cpu_time_us;
int64 bytes_per_second = benchmark_bytes_processed * 1000000 / cpu_time_us;
string heading = StringPrintf("%s/%d", name_.c_str(), test_case_num);
string human_readable_speed;
if (bytes_per_second < 1024) {
human_readable_speed = StringPrintf("%dB/s", bytes_per_second);
} else if (bytes_per_second < 1024 * 1024) {
human_readable_speed = StringPrintf(
"%.1fkB/s", bytes_per_second / 1024.0f);
} else if (bytes_per_second < 1024 * 1024 * 1024) {
human_readable_speed = StringPrintf(
"%.1fMB/s", bytes_per_second / (1024.0f * 1024.0f));
if (cpu_time_us <= 0) {
human_readable_speed = "?";
} else {
human_readable_speed = StringPrintf(
"%.1fGB/s", bytes_per_second / (1024.0f * 1024.0f * 1024.0f));
int64 bytes_per_second =
benchmark_bytes_processed * 1000000 / cpu_time_us;
if (bytes_per_second < 1024) {
human_readable_speed = StringPrintf("%dB/s", bytes_per_second);
} else if (bytes_per_second < 1024 * 1024) {
human_readable_speed = StringPrintf(
"%.1fkB/s", bytes_per_second / 1024.0f);
} else if (bytes_per_second < 1024 * 1024 * 1024) {
human_readable_speed = StringPrintf(
"%.1fMB/s", bytes_per_second / (1024.0f * 1024.0f));
} else {
human_readable_speed = StringPrintf(
"%.1fGB/s", bytes_per_second / (1024.0f * 1024.0f * 1024.0f));
}
}
fprintf(stderr,