Go: x/tools/cmd/goimports: too slow

Created on 14 Jul 2016 · 7Comments · Source: golang/go

Please answer these questions before submitting your issue. Thanks!

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

go version go1.6.2 darwin/amd64

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

GOARCH="amd64" GOBIN="" GOEXE="" GOHOSTARCH="amd64" GOHOSTOS="darwin" GOOS="darwin" GOPATH="/Users/romeo/code/go" GORACE="" GOROOT="/usr/local/Cellar/go/1.6.2/libexec" GOTOOLDIR="/usr/local/Cellar/go/1.6.2/libexec/pkg/tool/darwin_amd64" GO15VENDOREXPERIMENT="1" CC="clang" GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fno-common" CXX="clang++" CGO_ENABLED="1"

What did you do?
I've got a repo with a lot of vendored libraries:

```
$ tree vendor -d -L 2
vendor
├── github.com
│   ├── BurntSushi
│   ├── TheThingsNetwork
│   ├── apex
│   ├── boltdb
│   ├── brocaar
│   ├── dgrijalva
│   ├── eclipse
│   ├── fsnotify
│   ├── golang
│   ├── googollee
│   ├── gorilla
│   ├── hashicorp
│   ├── jacobsa
│   ├── labstack
│   ├── magiconair
│   ├── mattn
│   ├── mitchellh
│   ├── rcrowley
│   ├── robertkrimen
│   ├── smartystreets
│   ├── spf13
│   ├── tj
│   └── valyala
├── golang.org
│   └── x
├── google.golang.org
│   ├── appengine
│   ├── cloud
│   └── grpc
└── gopkg.in
├── bsm
├── redis.v3
├── sourcemap.v1
└── yaml.v2

35 directories
```

And now goimports is really slow:

$ time goimports routes/events.go 1>/dev/null goimports routes/events.go > /dev/null 3.45s user 9.69s system 331% cpu 3.964 total

However if I remove the vendored library and get the dependencies into my $GOPATH:

rm -r vendor go get

goimports is really fast again:

$ time goimports routes/events.go 1>/dev/null goimports routes/events.go 1>/dev/null 0.01s user 0.01s system 68% cpu 0.032 total

What did you expect to see?
Same performance on vendored libs and libs in $GOPATH.
What did you see instead?
A large performance difference.

FrozenDueToAge

Source

romeovs

👍1

Most helpful comment

Good timing. I was annoyed by goimports' performance recently and started investigating today during the Gophercon hack day. I have a change on my laptop to make things much faster.

It's doing way more work than necessary.

bradfitz on 14 Jul 2016

👍15 🎉5

All 7 comments

Good timing. I was annoyed by goimports' performance recently and started investigating today during the Gophercon hack day. I have a change on my laptop to make things much faster.

It's doing way more work than necessary.

bradfitz on 14 Jul 2016

👍15 🎉5

Can't wait for the CL.