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 package main 6 7 // Run a slow C function saving a CPU profile. 8 9 /* 10 #include <stdint.h> 11 12 int salt1; 13 int salt2; 14 15 void cpuHog() { 16 int foo = salt1; 17 int i; 18 19 for (i = 0; i < 100000; i++) { 20 if (foo > 0) { 21 foo *= foo; 22 } else { 23 foo *= foo + 1; 24 } 25 } 26 salt2 = foo; 27 } 28 29 void cpuHog2() { 30 } 31 32 struct cgoTracebackArg { 33 uintptr_t context; 34 uintptr_t sigContext; 35 uintptr_t* buf; 36 uintptr_t max; 37 }; 38 39 // pprofCgoTraceback is passed to runtime.SetCgoTraceback. 40 // For testing purposes it pretends that all CPU hits in C code are in cpuHog. 41 // Issue #29034: At least 2 frames are required to verify all frames are captured 42 // since runtime/pprof ignores the runtime.goexit base frame if it exists. 43 void pprofCgoTraceback(void* parg) { 44 struct cgoTracebackArg* arg = (struct cgoTracebackArg*)(parg); 45 arg->buf[0] = (uintptr_t)(cpuHog) + 0x10; 46 arg->buf[1] = (uintptr_t)(cpuHog2) + 0x4; 47 arg->buf[2] = 0; 48 } 49 */ 50 import "C" 51 52 import ( 53 "fmt" 54 "os" 55 "runtime" 56 "runtime/pprof" 57 "time" 58 "unsafe" 59 ) 60 61 func init() { 62 register("CgoPprof", CgoPprof) 63 } 64 65 func CgoPprof() { 66 runtime.SetCgoTraceback(0, unsafe.Pointer(C.pprofCgoTraceback), nil, nil) 67 68 f, err := os.CreateTemp("", "prof") 69 if err != nil { 70 fmt.Fprintln(os.Stderr, err) 71 os.Exit(2) 72 } 73 74 if err := pprof.StartCPUProfile(f); err != nil { 75 fmt.Fprintln(os.Stderr, err) 76 os.Exit(2) 77 } 78 79 t0 := time.Now() 80 for time.Since(t0) < time.Second { 81 C.cpuHog() 82 } 83 84 pprof.StopCPUProfile() 85 86 name := f.Name() 87 if err := f.Close(); err != nil { 88 fmt.Fprintln(os.Stderr, err) 89 os.Exit(2) 90 } 91 92 fmt.Println(name) 93 } 94