Slower cgo compilation after go1.1?

[decitrig]

I just upgraded to go1.1, and it appears that cgo compilation is dramatically slower now. Previously I hadn't noticed much difference between pure go & cgo compiles, but now its dramatically slower. For example:

package main

import (

"fmt"

//_ "github.com/go-gl/gl"

)

func main() {

fmt.Println("foo")

}

compiles in 0.139s, while 

package main

import (

"fmt"

_ "github.com/go-gl/gl"

)

func main() {

fmt.Println("foo")

}

compiles in 5.234s.

I hunted through the release notes but didn't see anything that would explain the difference - is this a bug in my setup, or is it reproducible?

--

rwsims

[Dave Cheney]

I suggest trying two things

1. compare the output of go build -x between 1.0 and 1.1, I suspect
there are more steps

2. run each of the -x steps by hand (you can just copy and paste them)
and time them yourself

At a guess I'd say this was the extra work put into the external
linking mode of cgo that is taking the additional time.

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[Vova Niki]

I think you just need to "go install" the cgo package and then it will be fast again 

[kane....@sendgrid.com]

Did you find a solution to this issue? I also think cgo is painfully slow now.

[Dave Cheney]

Kane,

It is likely that your old .a files (in $GOPATH/pkg) would be considered invalid by the compiler so it will be building them again.

Two things you can do

1. go build -v $PKG will show you the package it is compiling and any dependencies you need to compile before. If that is is surprisingly long, go to step 2

2. go install -v will install newer versions of those packages and reduce the amount that needs to be recompiled every time.

In summary, -v is a useful flag, I have several aliases set up so it is automatic, ie

alias gb='go install -v'