Are you transferring a lot of data? Are the servers non-cloud hosted? You could be encountering “tcp stalls”.
> On Aug 25, 2020, at 9:24 AM, Siddhesh Divekar <siddhesh.dive...@gmail.com> > wrote: > > > Clients are over the internet. > >> On Tue, Aug 25, 2020 at 3:25 AM Robert Engels <reng...@ix.netcom.com> wrote: >> The tcp protocol allows the connection to wait for hours. Go routines stuck >> in wait do not burn CPU. Are the clients local or remote (over internet)? >> >>>> On Aug 24, 2020, at 10:29 PM, Siddhesh Divekar >>>> <siddhesh.dive...@gmail.com> wrote: >>>> >>> >>> Robert, >>> >>> We will do the profiling next time we hit the issue again & see what is >>> happening. >>> This was the first time we saw the issue & don't want to get rid of http2 >>> advantages without making sure it's the actual culprit. >>> >>> Do you think in the meanwhile we should do what the discussion below >>> suggests anyways ? >>> https://stackoverflow.com/questions/42238695/goroutine-in-io-wait-state-for-long-time >>> >>> >>>> On Mon, Aug 24, 2020 at 5:37 PM Robert Engels <reng...@ix.netcom.com> >>>> wrote: >>>> I think it is too hard to tell with the limited information. It could be >>>> exhausted connections or it could be thrashing (the claim of high cpu) >>>> >>>> I think you want to run profiling capture prior to hitting the stick state >>>> - you should be able to detect what is happening. >>>> >>>> If the referenced issue is related I would assume you should be able to >>>> connect by forcing http/1. >>>> >>>> You can also try disabling http/2 and see if your issue goes away. >>>> >>>>> On Aug 24, 2020, at 6:15 PM, Siddhesh Divekar >>>>> <siddhesh.dive...@gmail.com> wrote: >>>>> >>>>> Hi Robert, >>>>> >>>>> Sorry I missed your earlier response. >>>>> >>>>> From what we saw our UI was blocked and since everything was unresponsive >>>>> we had to recover the system by sending sig abort. >>>>> >>>>>> On Mon, Aug 24, 2020 at 4:11 PM Siddhesh Divekar >>>>>> <siddhesh.dive...@gmail.com> wrote: >>>>>> Looking at the no. of go routines we have does this apply to this issue ? >>>>>> https://github.com/golang/go/issues/27044 >>>>>> >>>>>>> On Mon, Aug 24, 2020 at 12:54 PM Robert Engels <reng...@ix.netcom.com> >>>>>>> wrote: >>>>>>> Go routines in a waiting state should not be consuming CPU. Are you >>>>>>> certain they are not in constant transition from waiting to processing >>>>>>> - this could show up as high CPU usage while everything looks blocks. >>>>>>> >>>>>>> I would use pprof - github.com/robaho/goanalyzer might be of assistance >>>>>>> here to see the actual work being done. >>>>>>> >>>>>>>>> On Aug 24, 2020, at 9:10 AM, Siddhesh Divekar >>>>>>>>> <siddhesh.dive...@gmail.com> wrote: >>>>>>>>> >>>>>>>> >>>>>>>> Hi Ian, >>>>>>>> >>>>>>>> Thanks for replying. >>>>>>>> >>>>>>>> We have a go server running which handles user requests & collects >>>>>>>> data from various sources like gcp's cloud sql and big query. >>>>>>>> We are using shopify's sarama library to do kafka operations. >>>>>>>> >>>>>>>> There are seeing lots of go routines in waiting state for several >>>>>>>> minutes. >>>>>>>> Over the period of time around 587 goroutines have been spun up. >>>>>>>> >>>>>>>> We see that two go routines are stuck on gcp big query and we are >>>>>>>> using wait groups there. >>>>>>>> However, it's not clear why that would cause all other go routines to >>>>>>>> get hung & make cpu go high. >>>>>>>> >>>>>>>> goroutine 3332131 [semacquire, 79 minutes]: >>>>>>>> sync.runtime_Semacquire(0xc001c4fcf8) >>>>>>>> /usr/local/go/src/runtime/sema.go:56 +0x42 >>>>>>>> sync.(*WaitGroup).Wait(0xc001c4fcf0) >>>>>>>> /usr/local/go/src/sync/waitgroup.go:130 +0x64 >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*InsMgr).runParallelQuery(0xc001b54d40, >>>>>>>> 0xc002912c00, 0x330e1b0, 0xf, 0xc002912cf0, 0x3) >>>>>>>> /builds/fusionio/fusion/controller/stats/ins_mgr.go:488 +0x1d7 >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*InsMgr).GetMainUi(0xc001b54d40, >>>>>>>> 0xc002912db8, 0xc001870e68, 0x746121, 0xc0010fcaf8, 0x17) >>>>>>>> /builds/fusionio/fusion/controller/stats/ins_mgr.go:567 +0xa0d >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*Prefetcher).fetchMainUiTeamInterval(0xc001b56780, >>>>>>>> 0xc002356810, 0x24, 0x32f7b78, 0x5) >>>>>>>> /builds/fusionio/fusion/controller/stats/prefetcher.go:77 +0xf2 >>>>>>>> created by >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*Prefetcher).prefetchStats >>>>>>>> /builds/fusionio/fusion/controller/stats/prefetcher.go:100 >>>>>>>> +0xd8 >>>>>>>> >>>>>>>> >>>>>>>> goroutine 3332149 [semacquire, 79 minutes]: >>>>>>>> sync.runtime_Semacquire(0xc0015ede48) >>>>>>>> /usr/local/go/src/runtime/sema.go:56 +0x42 >>>>>>>> sync.(*WaitGroup).Wait(0xc0015ede40) >>>>>>>> /usr/local/go/src/sync/waitgroup.go:130 +0x64 >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*InsMgr).runParallelQuery(0xc001b54d40, >>>>>>>> 0xc00249dc00, 0x330e1b0, 0xf, 0xc00249dcf0, 0x3) >>>>>>>> /builds/fusionio/fusion/controller/stats/ins_mgr.go:488 +0x1d7 >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*InsMgr).GetMainUi(0xc001b54d40, >>>>>>>> 0xc00249ddb8, 0xc003200668, 0xc00407a520, 0xc003200590, 0x46ee97) >>>>>>>> /builds/fusionio/fusion/controller/stats/ins_mgr.go:567 +0xa0d >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*Prefetcher).fetchMainUiTeamInterval(0xc001b56780, >>>>>>>> 0xc002356ba0, 0x24, 0x32f7b78, 0x5) >>>>>>>> /builds/fusionio/fusion/controller/stats/prefetcher.go:77 +0xf2 >>>>>>>> created by >>>>>>>> git.fusion.io/fusionio/fusion/controller.git/stats.(*Prefetcher).prefetchStats >>>>>>>> /builds/fusionio/fusion/controller/stats/prefetcher.go:100 >>>>>>>> +0xd8 >>>>>>>> >>>>>>>> I found the link below which kind of co-relates to our scenario. >>>>>>>> https://stackoverflow.com/questions/42238695/goroutine-in-io-wait-state-for-long-time >>>>>>>> >>>>>>>> Most of the go routines in the backtrace are in a net/http package so >>>>>>>> our suspicion is that above bug in our code might be causing that. >>>>>>>> Even the bigquery is getting hung in net/http. >>>>>>>> >>>>>>>> We are using go version 1.13.8 & are running on gcp kubernetes cluster >>>>>>>> on ubuntu 18.04 docker. >>>>>>>> >>>>>>>> go env >>>>>>>> GO111MODULE="" >>>>>>>> GOARCH="amd64" >>>>>>>> GOBIN="" >>>>>>>> GOCACHE="/root/.cache/go-build" >>>>>>>> GOENV="/root/.config/go/env" >>>>>>>> GOEXE="" >>>>>>>> GOFLAGS="" >>>>>>>> GOHOSTARCH="amd64" >>>>>>>> GOHOSTOS="linux" >>>>>>>> GONOPROXY="" >>>>>>>> GONOSUMDB="" >>>>>>>> GOOS="linux" >>>>>>>> GOPATH="/root/go" >>>>>>>> GOPRIVATE="" >>>>>>>> GOPROXY="https://proxy.golang.org,direct"; >>>>>>>> GOROOT="/usr/local/go" >>>>>>>> GOSUMDB="sum.golang.org" >>>>>>>> GOTMPDIR="" >>>>>>>> GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64" >>>>>>>> GCCGO="gccgo" >>>>>>>> AR="ar" >>>>>>>> CC="gcc" >>>>>>>> CXX="g++" >>>>>>>> CGO_ENABLED="1" >>>>>>>> GOMOD="/builds/prosimoio/prosimo/pdash/go.mod" >>>>>>>> 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-build048009048=/tmp/go-build >>>>>>>> -gno-record-gcc-switches" >>>>>>>> >>>>>>>> Let me know if any other information is needed. >>>>>>>> >>>>>>>> >>>>>>>>> On Sat, Aug 22, 2020 at 12:30 PM Ian Lance Taylor <i...@golang.org> >>>>>>>>> wrote: >>>>>>>>> On Sat, Aug 22, 2020 at 12:06 PM Siddhesh Divekar >>>>>>>>> <siddhesh.dive...@gmail.com> wrote: >>>>>>>>> > >>>>>>>>> > We saw an issue with our process running in k8s on ubuntu 18.04. >>>>>>>>> > Most of the go routines are stuck for several minutes in http/http2 >>>>>>>>> > net code. >>>>>>>>> > >>>>>>>>> > Have you seen similar issues ? >>>>>>>>> > >>>>>>>>> > goroutine 2800143 [select, 324 minutes]: >>>>>>>>> > net/http.(*persistConn).readLoop(0xc00187d440) >>>>>>>>> > /usr/local/go/src/net/http/transport.go:2032 +0x999 created by >>>>>>>>> > net/http.(*Transport).dialConn >>>>>>>>> > /usr/local/go/src/net/http/transport.go:1580 +0xb0d goroutine >>>>>>>>> > 2738894 [IO wait, 352 minutes]: >>>>>>>>> > internal/poll.runtime_pollWait(0x7f5b61b280c0, 0x72, >>>>>>>>> > 0xffffffffffffffff) /usr/local/go/src/runtime/netpoll.go:184 +0x55 >>>>>>>>> > internal/poll.(*pollDesc).wait(0xc0017e7e18, 0x72, 0x1000, 0x1000, >>>>>>>>> > 0xffffffffffffffff) >>>>>>>>> > /usr/local/go/src/internal/poll/fd_poll_runtime.go:87 +0x45 >>>>>>>>> > internal/poll.(*pollDesc).waitRead(...) >>>>>>>>> > /usr/local/go/src/internal/poll/fd_poll_runtime.go:92 >>>>>>>>> > internal/poll.(*FD).Read(0xc0017e7e00, 0xc0044a9000, 0x1000, >>>>>>>>> > 0x1000, 0x0, 0x0, 0x0) >>>>>>>>> > /usr/local/go/src/internal/poll/fd_unix.go:169 +0x1cf >>>>>>>>> > net.(*netFD).Read(0xc0017e7e00, 0xc0044a9000, 0x1000, 0x1000, >>>>>>>>> > 0xc0026359e8, 0x49d7fd, 0xc0017e7e00) >>>>>>>>> > /usr/local/go/src/net/fd_unix.go:202 +0x4f >>>>>>>>> > net.(*conn).Read(0xc0000db8b8, 0xc0044a9000, 0x1000, 0x1000, 0x0, >>>>>>>>> > 0x0, 0x0) /usr/local/go/src/net/net.go:184 +0x68 >>>>>>>>> > net/http.(*connReader).Read(0xc004a4fec0, 0xc0044a9000, 0x1000, >>>>>>>>> > 0x1000, 0x0, 0x0, 0x0) /usr/local/go/src/net/http/server.go:785 >>>>>>>>> > +0xf4 bufio.(*Reader).fill(0xc003f1a360) >>>>>>>>> > /usr/local/go/src/bufio/bufio.go:100 +0x103 >>>>>>>>> > bufio.(*Reader).Peek(0xc003f1a360, 0x4, 0x0, 0x0, 0x0, 0x0, >>>>>>>>> > 0xc002635ad0) /usr/local/go/src/bufio/bufio.go:138 +0x4f >>>>>>>>> > net/http.(*conn).readRequest(0xc0028e1d60, 0x393ed20, 0xc0024e9780, >>>>>>>>> > 0x0, 0x0, 0x0) /usr/local/go/src/net/http/server.go:962 +0xb3b >>>>>>>>> > net/http.(*conn).serve(0xc0028e1d60, 0x393ed20, 0xc0024e9780) >>>>>>>>> > /usr/local/go/src/net/http/server.go:1817 +0x6d4 created by >>>>>>>>> > net/http.(*Server).Serve /usr/local/go/src/net/http/server.go:2928 >>>>>>>>> > +0x384 >>>>>>>>> > >>>>>>>>> > Is there a know issue or something obvious from the backtrace here. >>>>>>>>> >>>>>>>>> It's entirely normal for goroutines to sit in pollWait if they are >>>>>>>>> waiting for network I/O. There may be reasons why this is incorrect >>>>>>>>> for your program, but you'll have to tell us those reasons. >>>>>>>>> >>>>>>>>> Also, along with those reasons, please tell us the version of Go and >>>>>>>>> the exact environment that you are running. Thanks. >>>>>>>>> >>>>>>>>> Ian >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> -Siddhesh. >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "golang-nuts" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>>>>> an email to golang-nuts+unsubscr...@googlegroups.com. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/d/msgid/golang-nuts/CAMjfk%2BggC%2BwgwM_%2BM5ML0SKD3qJphCrif%3D4c2AqB9v6n%2Btw5Jw%40mail.gmail.com. >>>>>>>> <backtrace.txt> >>>>>> >>>>>> >>>>>> -- >>>>>> -Siddhesh. >>>>> >>>>> >>>>> -- >>>>> -Siddhesh. >>> >>> >>> -- >>> -Siddhesh. > > > -- > -Siddhesh. > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/CAMjfk%2BgQDHshxmGFiUFh6Ket9fp%2BwMuhgH6-FksyzMp9wz%2BXug%40mail.gmail.com. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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