github.com/geraldss/go/src@v0.0.0-20210511222824-ac7d0ebfc235/runtime/testdata/testprogcgo/threadpprof.go (about)

     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  // +build !plan9,!windows
     6  
     7  package main
     8  
     9  // Run a slow C function saving a CPU profile.
    10  
    11  /*
    12  #include <stdint.h>
    13  #include <time.h>
    14  #include <pthread.h>
    15  
    16  int threadSalt1;
    17  int threadSalt2;
    18  
    19  void cpuHogThread() {
    20  	int foo = threadSalt1;
    21  	int i;
    22  
    23  	for (i = 0; i < 100000; i++) {
    24  		if (foo > 0) {
    25  			foo *= foo;
    26  		} else {
    27  			foo *= foo + 1;
    28  		}
    29  	}
    30  	threadSalt2 = foo;
    31  }
    32  
    33  void cpuHogThread2() {
    34  }
    35  
    36  static int cpuHogThreadCount;
    37  
    38  struct cgoTracebackArg {
    39  	uintptr_t  context;
    40  	uintptr_t  sigContext;
    41  	uintptr_t* buf;
    42  	uintptr_t  max;
    43  };
    44  
    45  // pprofCgoThreadTraceback is passed to runtime.SetCgoTraceback.
    46  // For testing purposes it pretends that all CPU hits in C code are in cpuHog.
    47  void pprofCgoThreadTraceback(void* parg) {
    48  	struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg);
    49  	arg->buf[0] = (uintptr_t)(cpuHogThread) + 0x10;
    50  	arg->buf[1] = (uintptr_t)(cpuHogThread2) + 0x4;
    51  	arg->buf[2] = 0;
    52  	__sync_add_and_fetch(&cpuHogThreadCount, 1);
    53  }
    54  
    55  // getCPUHogThreadCount fetches the number of times we've seen cpuHogThread
    56  // in the traceback.
    57  int getCPUHogThreadCount() {
    58  	return __sync_add_and_fetch(&cpuHogThreadCount, 0);
    59  }
    60  
    61  static void* cpuHogDriver(void* arg __attribute__ ((unused))) {
    62  	while (1) {
    63  		cpuHogThread();
    64  	}
    65  	return 0;
    66  }
    67  
    68  void runCPUHogThread(void) {
    69  	pthread_t tid;
    70  	pthread_create(&tid, 0, cpuHogDriver, 0);
    71  }
    72  */
    73  import "C"
    74  
    75  import (
    76  	"fmt"
    77  	"os"
    78  	"runtime"
    79  	"runtime/pprof"
    80  	"time"
    81  	"unsafe"
    82  )
    83  
    84  func init() {
    85  	register("CgoPprofThread", CgoPprofThread)
    86  	register("CgoPprofThreadNoTraceback", CgoPprofThreadNoTraceback)
    87  }
    88  
    89  func CgoPprofThread() {
    90  	runtime.SetCgoTraceback(0, unsafe.Pointer(C.pprofCgoThreadTraceback), nil, nil)
    91  	pprofThread()
    92  }
    93  
    94  func CgoPprofThreadNoTraceback() {
    95  	pprofThread()
    96  }
    97  
    98  func pprofThread() {
    99  	f, err := os.CreateTemp("", "prof")
   100  	if err != nil {
   101  		fmt.Fprintln(os.Stderr, err)
   102  		os.Exit(2)
   103  	}
   104  
   105  	if err := pprof.StartCPUProfile(f); err != nil {
   106  		fmt.Fprintln(os.Stderr, err)
   107  		os.Exit(2)
   108  	}
   109  
   110  	C.runCPUHogThread()
   111  
   112  	t0 := time.Now()
   113  	for C.getCPUHogThreadCount() < 2 && time.Since(t0) < time.Second {
   114  		time.Sleep(100 * time.Millisecond)
   115  	}
   116  
   117  	pprof.StopCPUProfile()
   118  
   119  	name := f.Name()
   120  	if err := f.Close(); err != nil {
   121  		fmt.Fprintln(os.Stderr, err)
   122  		os.Exit(2)
   123  	}
   124  
   125  	fmt.Println(name)
   126  }