raceprof.go

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build (linux && amd64) || (freebsd && amd64)
     6  // +build linux,amd64 freebsd,amd64
     7  
     8  package main
     9  
    10  // Test that we can collect a lot of colliding profiling signals from
    11  // an external C thread. This used to fail when built with the race
    12  // detector, because a call of the predeclared function copy was
    13  // turned into a call to runtime.slicecopy, which is not marked nosplit.
    14  
    15  /*
    16  #include <signal.h>
    17  #include <stdint.h>
    18  #include <pthread.h>
    19  #include <sched.h>
    20  
    21  struct cgoTracebackArg {
    22  	uintptr_t  context;
    23  	uintptr_t  sigContext;
    24  	uintptr_t* buf;
    25  	uintptr_t  max;
    26  };
    27  
    28  static int raceprofCount;
    29  
    30  // We want a bunch of different profile stacks that collide in the
    31  // hash table maintained in runtime/cpuprof.go. This code knows the
    32  // size of the hash table (1 << 10) and knows that the hash function
    33  // is simply multiplicative.
    34  void raceprofTraceback(void* parg) {
    35  	struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
    36  	raceprofCount++;
    37  	arg->buf[0] = raceprofCount * (1 << 10);
    38  	arg->buf[1] = 0;
    39  }
    40  
    41  static void* raceprofThread(void* p) {
    42  	int i;
    43  
    44  	for (i = 0; i < 100; i++) {
    45  		pthread_kill(pthread_self(), SIGPROF);
    46  		sched_yield();
    47  	}
    48  	return 0;
    49  }
    50  
    51  void runRaceprofThread() {
    52  	pthread_t tid;
    53  	pthread_create(&tid, 0, raceprofThread, 0);
    54  	pthread_join(tid, 0);
    55  }
    56  */
    57  import "C"
    58  
    59  import (
    60  	"bytes"
    61  	"fmt"
    62  	"runtime"
    63  	"runtime/pprof"
    64  	"unsafe"
    65  )
    66  
    67  func init() {
    68  	register("CgoRaceprof", CgoRaceprof)
    69  }
    70  
    71  func CgoRaceprof() {
    72  	runtime.SetCgoTraceback(0, unsafe.Pointer(C.raceprofTraceback), nil, nil)
    73  
    74  	var buf bytes.Buffer
    75  	pprof.StartCPUProfile(&buf)
    76  
    77  	C.runRaceprofThread()
    78  	fmt.Println("OK")
    79  }
    80
View as plain text