runtime: GODEBUG=allocfreetrace=1 not working as go1.19.2 in go1.23.0

[bronze1man]

Go version

go version go1.23.0 darwin/amd64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/Users/a/Library/Caches/go-build'
GOENV='/Users/a/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/a/go/pkg/mod'
GONOPROXY='xxx.com'
GONOSUMDB='xxxx.com'
GOOS='darwin'
GOPATH='/Users/a/go'
GOPRIVATE='xxxx.com'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/darwin_amd64'
GOVCS=''
GOVERSION='go1.23.0'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/a/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/xxx/go.mod'
GOWORK='/xxx/go.work'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/mw/884f6hx53r56gd7zxsm1h8bm0000gp/T/go-build2465272456=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

go build -o ./bin/tAlloc3 ./make/tAlloc3
GODEBUG=allocfreetrace=1 ./bin/tAlloc3 &> ./tmp/2.log

my code

package main
import "fmt"
func main(){
	fmt.Println("abc")
}

What did you see happen?

nothing, only "abc"

What did you expect to see?

a lot of stack of alloc place of my code like in ./tmp/2.log

tracealloc(0xc000024000, 0x40, *runtime.p)
goroutine 0 [idle]:
runtime.mallocgc(0x40, 0x1098460, 0x1)
	/usr/local/go/src/runtime/malloc.go:1121 +0x7aa fp=0x7ff7bfeff6d8 sp=0x7ff7bfeff660 pc=0x100b9ea
runtime.makeslice(0x59960e85937f?, 0x105cbc1?, 0x1006a3f?)
	/usr/local/go/src/runtime/slice.go:103 +0x52 fp=0x7ff7bfeff700 sp=0x7ff7bfeff6d8 pc=0x1045c72
runtime.procresize(0x8)
	/usr/local/go/src/runtime/proc.go:4822 +0x15c fp=0x7ff7bfeff7b8 sp=0x7ff7bfeff700 pc=0x103d53c
runtime.schedinit()
	/usr/local/go/src/runtime/proc.go:722 +0x1d3 fp=0x7ff7bfeff810 sp=0x7ff7bfeff7b8 pc=0x1034713
runtime.rt0_go()
	/usr/local/go/src/runtime/asm_amd64.s:345 +0x11e fp=0x7ff7bfeff818 sp=0x7ff7bfeff810 pc=0x105ab3e 

[gabyhelp]

Related Issues and Documentation

• Test report unexpected error when race detection is enabled #50323 (closed)
• debug/pe: fatal error: runtime: out of memory on NewFile #43827
• runtime: fatal error: sweep increased allocation count in go1.7 #16778 (closed)
• runtime: gcstoptheworld=2 doesn't work #53885 (closed)
• cmd/compile: stringtoslicebytetmp optimization on unescaped slice #38501 (closed)
• runtime: large stack makes the program hang #26154 (closed)
• runtime: Unable to build go project on macOS 10.12 beta 4 #16575 (closed)
• runtime: Encountering strange build stack trace when running go build #16627 (closed)
• runtime: go1.4 "fatal error: bad pointer" #12729 (closed)
• runtime: traceback stuck in runtime.systemstack #55851 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[bronze1man]

Then I tried the new api from "runtime.trace" and "golang.org/x/exp/trace". I can not get stacktrace of every alloc.

package main

import (
	"os"
	"runtime/trace"
	trace2 "golang.org/x/exp/trace"
	"fmt"
)

func main(){
	runTrace()
	f,err:=os.Open("./tmp/1.trace")
	if err!=nil{
		panic(err)
	}
	r,err:=trace2.NewReader(f)
	if err!=nil{
		panic(err)
	}
	for {
		event,err:=r.ReadEvent()
		if err!=nil{
			fmt.Println(err)
			return
		}
		if event.Kind()!=trace2.EventExperimental{
			continue
		}
		exp:=event.Experimental()
		if exp.Name=="HeapObjectAlloc"{
			fmt.Println(event.String())
			fmt.Println(event.Stack())
		}
	}
}

func runTrace(){
	os.Setenv("GODEBUG", "traceallocfree=1")
	f,err:=os.Create("./tmp/1.trace")
	if err!=nil{
		panic(err)
	}
	trace.Start(f)
	defer trace.Stop()
	toTrace()
}

func toTrace(){
	fmt.Println(`abc`)
}

I can not get stacktrace of every alloc:

abc
M=140704665246592 P=0 G=1 Experimental Time=98720547720960 Name=HeapObjectAlloc ArgNames=[id type] Args=[8288 10]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547721472 Name=HeapObjectAlloc ArgNames=[id type] Args=[61454 0]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547721856 Name=HeapObjectAlloc ArgNames=[id type] Args=[60426 11]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547722048 Name=HeapObjectAlloc ArgNames=[id type] Args=[61468 0]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547722624 Name=HeapObjectAlloc ArgNames=[id type] Args=[10334 12]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547723136 Name=HeapObjectAlloc ArgNames=[id type] Args=[3744 13]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547730816 Name=HeapObjectAlloc ArgNames=[id type] Args=[61482 0]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547731072 Name=HeapObjectAlloc ArgNames=[id type] Args=[8291 10]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547731264 Name=HeapObjectAlloc ArgNames=[id type] Args=[61496 0]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547731520 Name=HeapObjectAlloc ArgNames=[id type] Args=[60436 11]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547731840 Name=HeapObjectAlloc ArgNames=[id type] Args=[10336 14]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547732096 Name=HeapObjectAlloc ArgNames=[id type] Args=[3800 13]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547735616 Name=HeapObjectAlloc ArgNames=[id type] Args=[8294 15]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547735808 Name=HeapObjectAlloc ArgNames=[id type] Args=[3856 13]
{<nil> 0}
M=123145502023680 P=1 G=6 Experimental Time=98720547783744 Name=HeapObjectAlloc ArgNames=[id type] Args=[72704 16]
{<nil> 0}
M=123145502023680 P=1 G=6 Experimental Time=98720547790848 Name=HeapObjectAlloc ArgNames=[id type] Args=[73728 17]
{<nil> 0}
M=123145502023680 P=1 G=7 Experimental Time=98720547806720 Name=HeapObjectAlloc ArgNames=[id type] Args=[74752 16]
{<nil> 0}
M=123145502023680 P=1 G=7 Experimental Time=98720547807488 Name=HeapObjectAlloc ArgNames=[id type] Args=[73740 17]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547826816 Name=HeapObjectAlloc ArgNames=[id type] Args=[62608 18]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547827776 Name=HeapObjectAlloc ArgNames=[id type] Args=[60446 18]
{<nil> 0}
M=140704665246592 P=0 G=1 Experimental Time=98720547828800 Name=HeapObjectAlloc ArgNames=[id type] Args=[139284 18]
{<nil> 0}
EOF

[bronze1man]

GODEBUG=allocfreetrace=1 is very good tool to make my code faster with less heap alloc.
Now it is not working...

[MikeMitchellWebDev]

runtime: remove allocfreetrace: https://go-review.googlesource.com/c/go/+/583376