goroutine泄露排查
定性goroutine泄漏
现象1: goroutine数量持续增长（本文例子使用了goroutine pool，没有持续增长现象）
现象2: 内存持续增长
go tool pprof http://0.0.0.0:6060/debug/pprof/goroutine查看top，runtime.gopark接近100%
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root@ip:~/pprof# go tool pprof http://0.0.0.0:6060/debug/pprof/goroutine File: my-tracing Type: goroutine Time: Jul 4, 2023 at 11:00am (+08) Entering interactive mode (type "help" for commands, "o" for options) (pprof) top Showing nodes accounting for 2571, 99.30% of 2589 total Dropped 117 nodes (cum <= 12) Showing top 10 nodes out of 61 flat flat% sum% cum cum% 2571 99.30% 99.30% 2571 99.30% runtime.gopark 0 0% 99.30% 24 0.93% bufio.(*Reader).Read 0 0% 99.30% 421 16.26% git.***.ConsumeTraces 0 0% 99.30% 421 16.26% git.***.ConsumeTraces 0 0% 99.30% 1779 68.71% git.**.func1 0 0% 99.30% 1779 68.71% git.**.processTraces 0 0% 99.30% 90 3.48% git.**.AddToCurrentBatch 0 0% 99.30% 16 0.62% github.com/panjf2000/ants.(*Pool).Submit 0 0% 99.30% 16 0.62% github.com/panjf2000/ants.(*Pool).retrieveWorker 0 0% 99.30% 27 1.04% github.com/panjf2000/ants.(*Pool).revertWorker (pprof)
命令行
go tool pprof http://0.0.0.0:6060/debug/pprof/goroutine
top: 查看函数调用占比
traces: 查看所有goroutine的调用栈
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(pprof) traces
File: my-tracing
Type: goroutine
Time: Jul 4, 2023 at 6:01pm (+08)
-----------+-------------------------------------------------------
1875 runtime.gopark
runtime.goparkunlock (inline)
runtime.semacquire1
sync.runtime_SemacquireMutex
sync.(*Mutex).lockSlow
sync.(*Mutex).Lock (inline)
sync.(*Map).LoadOrStore
git.**.processTraces
git.**.ConsumeTraces.func1
github.com/panjf2000/ants.(*goWorker).run.func1
-----------+-------------------------------------------------------
.....
1875个goroutine执行了该调用栈，然后runtime.gopark阻塞挂起
list: 查看函数代码，远程机器不能支持
Debug=1，定位函数调用栈
wget http://ip:port/debug/pprof/goroutine?debug=1下载pprof
wim 'goroutine?debug=1'打开文件，搜索阻塞函数名:samplingPolicyOnTickPerShards
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1 @ 0x439bb6 0x44aa2c 0x44aa06 0x466fa5 0x483471 0xd1d53d 0xd16cb2 0xd16ca4 0x46b1e1
# 0x466fa4 sync.runtime_Semacquire+0x24 /usr/local/go/src/runtime/sema.go:56
# 0x483470 sync.(*WaitGroup).Wait+0x70 /usr/local/go/src/sync/waitgroup.go:130
# 0xd1d53c git.**.samplingPolicyOnTickPerShards+0xfc /apps/vendor/git.**/processor.go:245
# 0xd16cb1 git.**/timeutils.(*PolicyTicker).OnTick+0x31 /apps/vendor/git.**/ticker_helper.go:56
# 0xd16ca3 git.**/timeutils.(*PolicyTicker).Start.func1+0x23 /apps/vendor/git.**/ticker_helper.go:47
1 @ 0x439bb6 0x44aa2c 0x44aa06 0x466fa5 0x483471 0xd1e1af 0xcc048f 0x262e86d 0x25eb5f3 0xcb3eef 0xcb20f8 0xb00dac 0xacf39b 0xaf777c 0xacf3c3 0xacf2eb 0xcb1fb8 0xad0112 0xad3e4a 0xacdc38 0x46b1e1
Debug=2，查看goroutine阻塞时间
wget http://ip:port/debug/pprof/goroutine?debug=2下载pprof
wim 'goroutine?debug=2'打开文件,搜索阻塞函数名:samplingPolicyOnTickPerShards
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goroutine 279 [semacquire, 892 minutes]:
sync.runtime_Semacquire(0xc001298f30)
/usr/local/go/src/runtime/sema.go:56 +0x25
sync.(*WaitGroup).Wait(0xc00179c1e0)
/usr/local/go/src/sync/waitgroup.go:130 +0x71
git.**.samplingPolicyOnTickPerShards(0xc0009d65a0)
/apps/vendor/git.**/processor.go:245 +0xfd
git.**/timeutils.(*PolicyTicker).OnTick(...)
/apps/vendor/git.**/ticker_helper.go:56
git.**/timeutils.(*PolicyTicker).Start.func1()
/apps/vendor/git.**/ticker_helper.go:47 +0x32
created by git.**/timeutils.(*PolicyTicker).Start
/apps/vendor/git.**/ticker_helper.go:43 +0xb2
- goroutine id: 279
- 当前状态：semacquire
- 阻塞了：892 minutes
总结
- 第一步：定性是否为goroutine泄漏
- 第二步：利用debug=1和debug=2定位代码函数
- 第三步：梳理代码逻辑，修复问题
参考
- 实战Go内存泄露：https://lessisbetter.site/2019/05/18/go-goroutine-leak/
This post is licensed under CC BY 4.0 by the author.