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authorGravatar Yuqian Li <liyuqian@google.com>2017-09-21 13:23:49 -0400
committerGravatar Skia Commit-Bot <skia-commit-bot@chromium.org>2017-09-21 17:44:53 +0000
commit3528eb319019b415c840349d2b35739bc2b38833 (patch)
treeec124c85f290b579b1fec7cb694601564ae5b5f6 /bench
parent3b7658a4752e1332c684ad757686ce9ee0e5fbd1 (diff)
Run the first bench for 1000ms to warm up the nanobench if FLAGS_ms < 1000.
Otherwise, the first few benches' measurements will be inaccurate. For example, without this CL, the first few measurements are: 337ns, 566µs, 1000µs, ... without "--ms 1000" arg 211ns, 285µs, 874µs, ... with "--ms 1000" arg With this CL, the first few measurements are: 195ns, 296µs, 1.03ms, ... without "--ms 1000" arg 204ns, 280µs, 859µs, ... with "--ms 1000" arg In the example above, the first two measurements are vastly (>50%) different without this CL. I think that's the reason why I keep using "--ms 1000" arg locally. But it's really only necessary for the first bench to warm up nanobench. It's a waste to apply "--ms 1000" to all the following benches. Bug: skia: Change-Id: I1924ba3ff9185ed89aeda72794fafd1fe6625eef Reviewed-on: https://skia-review.googlesource.com/49742 Reviewed-by: Yuqian Li <liyuqian@google.com> Commit-Queue: Yuqian Li <liyuqian@google.com>
Diffstat (limited to 'bench')
-rw-r--r--bench/nanobench.cpp9
1 files changed, 9 insertions, 0 deletions
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index d784439bb4..04583309ce 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -1284,6 +1284,15 @@ int main(int argc, char** argv) {
? setup_gpu_bench(target, bench.get(), maxFrameLag)
: setup_cpu_bench(overhead, target, bench.get());
+ if (runs == 0 && FLAGS_ms < 1000) {
+ // Run the first bench for 1000ms to warm up the nanobench if FLAGS_ms < 1000.
+ // Otherwise, the first few benches' measurements will be inaccurate.
+ auto stop = now_ms() + 1000;
+ do {
+ time(loops, bench.get(), target);
+ } while (now_ms() < stop);
+ }
+
if (FLAGS_ms) {
samples.reset();
auto stop = now_ms() + FLAGS_ms;