runtime: TestPingPongHog fails randomly

[zhangyunhao116]

What version of Go are you using (go version)?

$ go version
go version go1.18.1 linux/amd64

Does this issue reproduce with the latest release?

Yes. Also in the latest master.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/zyh/.cache/go-build"
GOENV="/home/zyh/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/zyh/go/pkg/mod"
GOOS="linux"
GOPATH="/home/zyh/go"
GOPROXY="https://goproxy.cn,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.google.cn"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18.1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3288130196=/tmp/go-build -gno-record-gcc-switches"

What did you do?

$ go test -run=PingPongHog runtime -count=10

What did you expect to see?

Test succeed.

What did you see instead?

Test fails randomly.

--- FAIL: TestPingPongHog (0.10s)
proc_test.go:486: want hogCount/lightCount in [0.2, 5]; got 108000000/7825000 = 13.801916932907348

[thanm]

I am not able to reproduce this on my laptop or my workstation:

workstation:

sh /tmp/x.sh
iter 1
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.105s
iter 2
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.105s
iter 3
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.098s
iter 4
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.120s
iter 5
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.097s
iter 6
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.099s
iter 7
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.110s
iter 8
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.110s
iter 9
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.110s
iter 10
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.113s

laptop:

sh /tmp/x.sh
iter 1
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.040s
iter 2
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.043s
iter 3
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.042s
iter 4
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.047s
iter 5
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.040s
iter 6
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.044s
iter 7
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.046s
iter 8
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.041s
iter 9
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.042s
iter 10
go test -run=PingPongHog runtime -count=10
ok  	runtime	1.041s

Both machines are linux/amd64.

Wondering if there may be some other environmental issue (OS release or kernel version, or ???).

[zhangyunhao116]

@thanm Thanks! I am also not able to reproduce this on my another linux/amd64 PC, it maybe other reasons. Closed.