cmd/compile: slow escape analysis in large package in the typescript compiler

[Jorropo]

Go version

go version go1.24.1 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v3'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/tmp/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/hugo/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1913709825=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/hugo/k/go/src/go.mod'
GOMODCACHE='/home/hugo/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/hugo/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/hugo/k/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/hugo/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/home/hugo/k/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.1'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

I've tried compiling the new typescript compiler and it took 70s:

________________________________________________________
Executed in   70.51 secs    fish           external
   usr time  159.17 secs  543.00 micros  159.17 secs
   sys time    5.49 secs  249.00 micros    5.49 secs

What tipped me off to an issue is the poor 160 ÷ 70 ≈ 2.3 multi-core utilization.

The biggest outlier is github.com/microsoft/typescript-go/internal/checker:

github.com/microsoft/typescript-go/internal/checker

________________________________________________________
Executed in   44.97 secs    fish           external
   usr time   50.51 secs  413.00 micros   50.51 secs
   sys time    0.32 secs  142.00 micros    0.32 secs

A CPU profile is very suspicious, almost all of the time is spent here:

I've added a couple of debug statements in theses loops:
There is a suspicious:

walkAll 36466 <nil> <nil>

36466 is the length of the queue.
This steadily slowly goes down, walkOne roughly does ~5000 iterations for each iteration of walkAll

[gabyhelp]

Related Issues

• cmd/dist: `GOMAXPROCS=2 runtime -cpu=1,2,4 -quick` makes poor use of CPU resources, increasing `all.bat` latency #65164 (closed)
• cmd/compile: compileSSA takes a long time on very large (generated) functions #30077
• mime/quotedprintable: Go 2: Why takes so long to compile? (At least 8min+) #39912 (closed)
• cmd/compile: long build time (45 seconds) for a small package (1500 source lines of code) #65097 (closed)
• Compilator takes unpredictable build times and I have no idea what it's doing and why it's doing #70691 (closed)
• cmd/go: cache results of exec.LookPath #36768 (closed)
• runtime: `-quick` tests aren't quick with reduced GOMAXPROCS #53818 (closed)
• cmd/go: add duration on each -x of go build to know which pkg that slow #37591 (closed)
• affected/package: #57137 (closed)
• cmd/compile/internal/escape: performance issue #67313 (closed)

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

[Jorropo]

I've tried to bisect it but 1.22 is the last version I could easily test as this is a modern codebase and it is just as bad.

[jakebailey]

I said this on the gopher slack, but I'm not sure entirely if this is a regression in Go or just our package scaling poorly as it grew during the port; I plan to gather some data over all of the commits in the repo to see what that looks like.

Of course, a bug in the compiler would certainly be "good news" from the PoV that we wouldn't have to figure out how to break apart the monster.

[Jorropo]

For context this package has 2652 functions, 1669 are *checker.Checker methods.

[prattmic]

cc @golang/compiler

[dr2chase]

If there's a copy-paste recipe for building the new typescript compiler to show this problem, that would help. I could probably figure it out, but the bug author already knows the answer and that way we'll know that we are looking at the same problem.

[jakebailey]

The repo doesn't require any special tooling to build any of the Go code there at all, so it's just:

$ git clone https://github.com/microsoft/typescript-go.git
$ cd typescript-go
$ go build ./internal/checker

[Jorropo]

I could probably figure it out, but the bug author already knows the answer and that way we'll know that we are looking at the same problem.

How am I gonna claim the fix if I help you investigating it ?
Jokes aside, mb 😄

[prattmic]

FWIW, after internal/checker (60s), the next slowest package is internal/ast, which takes 16s on my machine. That appears to be a different issue. Escape analysis doesn't show up at all. Nothing in particular stands out to me in the profile.