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author | Elliott Hughes | 2014-05-30 21:00:03 -0500 |
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committer | Elliott Hughes | 2014-06-02 12:32:55 -0500 |
commit | 5d9a7ba0dc9c24ed4e4efa9cac0e796fd524b308 (patch) | |
tree | 4674df3b5064cb38211453b6e887c364f0c66f05 /benchmarks | |
parent | 831405b749d15a11fb947a40d61fd858e952d860 (diff) | |
download | platform-bionic-5d9a7ba0dc9c24ed4e4efa9cac0e796fd524b308.tar.gz platform-bionic-5d9a7ba0dc9c24ed4e4efa9cac0e796fd524b308.tar.xz platform-bionic-5d9a7ba0dc9c24ed4e4efa9cac0e796fd524b308.zip |
Avoid a system call in 'gettid'.
System calls can be pretty slow. This is mako, which has one of our
lowest latencies:
iterations ns/op
BM_unistd_getpid 10000000 209
BM_unistd_gettid 200000000 8
Bug: 15297299 (kernel panic from too many gettid calls)
Bug: 15315766 (excessive gettid overhead in liblogd)
Change-Id: I49656c0fc5b5d092390264a59e4f2c0d8a8b1aeb
Diffstat (limited to 'benchmarks')
-rw-r--r-- | benchmarks/unistd_benchmark.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/benchmarks/unistd_benchmark.cpp b/benchmarks/unistd_benchmark.cpp index e839bf8b..12b788ac 100644 --- a/benchmarks/unistd_benchmark.cpp +++ b/benchmarks/unistd_benchmark.cpp | |||
@@ -28,3 +28,14 @@ static void BM_unistd_getpid(int iters) { | |||
28 | StopBenchmarkTiming(); | 28 | StopBenchmarkTiming(); |
29 | } | 29 | } |
30 | BENCHMARK(BM_unistd_getpid); | 30 | BENCHMARK(BM_unistd_getpid); |
31 | |||
32 | static void BM_unistd_gettid(int iters) { | ||
33 | StartBenchmarkTiming(); | ||
34 | |||
35 | for (int i = 0; i < iters; ++i) { | ||
36 | gettid(); | ||
37 | } | ||
38 | |||
39 | StopBenchmarkTiming(); | ||
40 | } | ||
41 | BENCHMARK(BM_unistd_gettid); | ||