x/tools/cmd/goimports: too slow

romeovs commented 8 years ago

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.

bradfitz commented 8 years ago

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.

josharian commented 8 years ago

Can't wait for the CL.

gopherbot commented 8 years ago

CL https://golang.org/cl/24941 mentions this issue.

gopherbot commented 8 years ago

CL https://golang.org/cl/24948 mentions this issue.

gopherbot commented 8 years ago

CL https://golang.org/cl/24971 mentions this issue.

gopherbot commented 8 years ago

CL https://golang.org/cl/25001 mentions this issue.

bradfitz commented 8 years ago

I think it's fast enough to close this now.

golang / go

x/tools/cmd/goimports: too slow #16367