From c6965ad63fc66e02f37c9dcfc381c898983cec16 Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Tue, 17 May 2022 17:52:43 -0400 Subject: [PATCH] runtime: deflake TestCgoPprofThread In TestCgoPprofThread, the (fake) cgo traceback function pretends all C CPU samples are in cpuHogThread. But if a profiling signal lands in C code but outside of that thread, e.g. before/when the thread is created, we will get a sample which looks like Go calls into cpuHogThread. This CL makes the cgo traceback function only return cpuHogThread PCs when a signal lands on that thread. May fix #52726. Change-Id: I21c40f974d1882508626faf3ac45e8347fec31c4 Reviewed-on: https://go-review.googlesource.com/c/go/+/406934 Run-TryBot: Cherry Mui TryBot-Result: Gopher Robot Reviewed-by: Ian Lance Taylor --- src/runtime/testdata/testprogcgo/threadpprof.go | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/src/runtime/testdata/testprogcgo/threadpprof.go b/src/runtime/testdata/testprogcgo/threadpprof.go index ec5e750da9..70717e0099 100644 --- a/src/runtime/testdata/testprogcgo/threadpprof.go +++ b/src/runtime/testdata/testprogcgo/threadpprof.go @@ -17,6 +17,8 @@ package main int threadSalt1; int threadSalt2; +static pthread_t tid; + void cpuHogThread() { int foo = threadSalt1; int i; @@ -42,12 +44,16 @@ struct cgoTracebackArg { }; // pprofCgoThreadTraceback is passed to runtime.SetCgoTraceback. -// For testing purposes it pretends that all CPU hits in C code are in cpuHog. +// For testing purposes it pretends that all CPU hits on the cpuHog +// C thread are in cpuHog. void pprofCgoThreadTraceback(void* parg) { struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg); - arg->buf[0] = (uintptr_t)(cpuHogThread) + 0x10; - arg->buf[1] = (uintptr_t)(cpuHogThread2) + 0x4; - arg->buf[2] = 0; + if (pthread_self() == tid) { + arg->buf[0] = (uintptr_t)(cpuHogThread) + 0x10; + arg->buf[1] = (uintptr_t)(cpuHogThread2) + 0x4; + arg->buf[2] = 0; + } else + arg->buf[0] = 0; } static void* cpuHogDriver(void* arg __attribute__ ((unused))) { @@ -58,7 +64,6 @@ static void* cpuHogDriver(void* arg __attribute__ ((unused))) { } void runCPUHogThread(void) { - pthread_t tid; pthread_create(&tid, 0, cpuHogDriver, 0); } */ -- 2.50.0