cmd/test: caching test results takes 50 seconds

[rillig]

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

go version go1.13.1 windows/amd64

Does this issue reproduce with the latest release?

yes

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

go env Output

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\rillig\AppData\Local\go-build
set GOENV=C:\Users\rillig\AppData\Roaming\go\env
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\rillig\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=c:\go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=c:\go\pkg\tool\windows_amd64
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\rillig\Program Files\cygwin\tmp\go-build091584506=/tmp/go-build -gno-record-gcc-switches
go: failed to remove work dir: GetFileInformationByHandle C:\Users\rillig\Program Files\cygwin\tmp\go-build091584506\NUL: Unzulässige Funktion.

The last line of the above output looks interesting in itself.

What did you do?

cd "$GOPATH/src"
go get github.com/rillig/pkglint
mv github.com/rillig/pkglint to netbsd.org/pkglint
cd netbsd.org/pkglint

go generate ./... && time go test ./...
# takes 20 seconds to run the test
# then, takes 50 seconds to cache the test results
go generate ./... && time go test -test.count 1 ./...
# takes 20 seconds

What did you expect to see?

Caching the test results needs less than a second.

What did you see instead?

Caching the test results takes much longer than running the test.
It doesn't matter whether I run the tests from within cmd.exe or Cygwin.

[toothrot]

That go env failure sounds similar to #30789, which @bcmills, @bradfitz and @alexbrainman have some experience with. I'm wondering if it's related to the comment added in golang.org/cl/172337.

[bcmills]

Both of those seem like symptoms of an unusually slow filesystem.

@rillig, what kind of disk is your GOCACHE hosted on, and do you have any utilities (such as antivirus scanners) running for files on that disk?

[rillig]

@bcmills The GOCACHE is on an SSD, therefore I expect it to be pretty fast. The antivirus scanner sounds plausible, therefore I tried to reproduce it today, but it was reasonably fast. I'll try again tomorroy, to get another measuring.

[alexbrainman]

@rillig I don't have Cygwin. I tried guessing your repro, but failed

c:\Users\Alex\dev\go\src>cd %GOPATH%

c:\Users\Alex\dev>cd src

c:\Users\Alex\dev\src>go get github.com/rillig/pkglint
package netbsd.org/pkglint/getopt: unrecognized import path "netbsd.org/pkglint/getopt": reading https://netbsd.org/pkglint/getopt?go-get=1: 404 Not Found
package netbsd.org/pkglint/histogram: unrecognized import path "netbsd.org/pkglint/histogram": reading https://netbsd.org/pkglint/histogram?go-get=1: 404 Not Found
package netbsd.org/pkglint/licenses: unrecognized import path "netbsd.org/pkglint/licenses": reading https://netbsd.org/pkglint/licenses?go-get=1: 404 Not Found
package netbsd.org/pkglint/pkgver: unrecognized import path "netbsd.org/pkglint/pkgver": reading https://netbsd.org/pkglint/pkgver?go-get=1: 404 Not Found
package netbsd.org/pkglint/regex: unrecognized import path "netbsd.org/pkglint/regex": reading https://netbsd.org/pkglint/regex?go-get=1: 404 Not Found
package netbsd.org/pkglint/textproc: unrecognized import path "netbsd.org/pkglint/textproc": reading https://netbsd.org/pkglint/textproc?go-get=1: 404 Not Found
package netbsd.org/pkglint/trace: unrecognized import path "netbsd.org/pkglint/trace": reading https://netbsd.org/pkglint/trace?go-get=1: 404 Not Found

c:\Users\Alex\dev\src>

Alex

[mvdan]

Closing old issues that still have the WaitingForInfo label where enough details to investigate weren't provided. Feel free to leave a comment with more details and we can reopen.