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Source file src/runtime/testdata/testprogcgo/raceprof.go

Documentation: runtime/testdata/testprogcgo

  // Copyright 2016 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // +build linux,amd64
  
  package main
  
  // Test that we can collect a lot of colliding profiling signals from
  // an external C thread. This used to fail when built with the race
  // detector, because a call of the predeclared function copy was
  // turned into a call to runtime.slicecopy, which is not marked nosplit.
  
  /*
  #include <signal.h>
  #include <stdint.h>
  #include <pthread.h>
  #include <sched.h>
  
  struct cgoTracebackArg {
  	uintptr_t  context;
  	uintptr_t  sigContext;
  	uintptr_t* buf;
  	uintptr_t  max;
  };
  
  static int raceprofCount;
  
  // We want a bunch of different profile stacks that collide in the
  // hash table maintained in runtime/cpuprof.go. This code knows the
  // size of the hash table (1 << 10) and knows that the hash function
  // is simply multiplicative.
  void raceprofTraceback(void* parg) {
  	struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
  	raceprofCount++;
  	arg->buf[0] = raceprofCount * (1 << 10);
  	arg->buf[1] = 0;
  }
  
  static void* raceprofThread(void* p) {
  	int i;
  
  	for (i = 0; i < 100; i++) {
  		pthread_kill(pthread_self(), SIGPROF);
  		sched_yield();
  	}
  	return 0;
  }
  
  void runRaceprofThread() {
  	pthread_t tid;
  	pthread_create(&tid, 0, raceprofThread, 0);
  	pthread_join(tid, 0);
  }
  */
  import "C"
  
  import (
  	"bytes"
  	"fmt"
  	"runtime"
  	"runtime/pprof"
  	"unsafe"
  )
  
  func init() {
  	register("CgoRaceprof", CgoRaceprof)
  }
  
  func CgoRaceprof() {
  	runtime.SetCgoTraceback(0, unsafe.Pointer(C.raceprofTraceback), nil, nil)
  
  	var buf bytes.Buffer
  	pprof.StartCPUProfile(&buf)
  
  	C.runRaceprofThread()
  	fmt.Println("OK")
  }
  

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