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> -- 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/A3102E99-2CDA-40EF-BEDF-8E5DF3DF3349%40ix.netcom.com.
