Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

net/http: transferWriter.doBodyCopy() calls io.Copy() resulting in many buffer allocations #57202

Open
mmatczuk opened this issue Dec 9, 2022 · 3 comments · May be fixed by #57205
Open

net/http: transferWriter.doBodyCopy() calls io.Copy() resulting in many buffer allocations #57202

mmatczuk opened this issue Dec 9, 2022 · 3 comments · May be fixed by #57205
Assignees
@neild
Labels
NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. Performance
Milestone
Backlog

Comments

@mmatczuk
Copy link

mmatczuk commented Dec 9, 2022 •
edited

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

$ go version go1.19.4 darwin/arm64

Does this issue reproduce with the latest release?

Yes

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

go env Output
GO111MODULE="on"
GOARCH="arm64"
GOBIN=""
GOCACHE="/Users/michal/Library/Caches/go-build"
GOENV="/Users/michal/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/michal/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/michal/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/Users/michal/sdk/go1.19.4"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/Users/michal/sdk/go1.19.4/pkg/tool/darwin_arm64"
GOVCS=""
GOVERSION="go1.19.4"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/7q/nyynjpwj5p19npby48ykjpx00000gn/T/go-build3980036370=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

I have HTTP proxy server proxying plain HTTP 1.1 requests based on google/martian. When I profile the memory allocations I see that transferWriter.doBodyCopy() calls io.Copy() resulting in many buffer allocations. The profile graph is attached below.

Screenshot 2022-12-09 at 13 40 11

I think doBodyCopy() could use copyBufPool we have in response.ReadFrom() to avoid the allocations.
@mmatczuk mmatczuk changed the title net/http: transferWriter.doBodyCopy calls io.Copy reslting net/http: transferWriter.doBodyCopy() calls io.Copy() resulting in many buffer allocations Dec 9, 2022
@seankhliao seankhliao added Performance NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. labels Dec 9, 2022
mmatczuk pushed a commit to mmatczuk/go that referenced this issue Dec 9, 2022
net/http: use copyBufPool in transferWriter.doBodyCopy()
ba09cda 
This patch is a followup to 6fd82d8.
It applies copyBufPool optimization to transferWriter.doBodyCopy().
The function is very frequently used - everytime Request or Response is written to a wire.
Without this patch for every Request and Response processed, if there is a body, we need to allocate and GC a 32k buffer.
This is quickly causing GC pressure.

Fixes golang#57202
@mmatczuk mmatczuk linked a pull request Dec 9, 2022 that will close this issue
Open
@gopherbot
Copy link

Change https://go.dev/cl/456435 mentions this issue: net/http: use copyBufPool in transferWriter.doBodyCopy()

@neild
Copy link
Contributor

neild commented Dec 9, 2022

I wonder if io.Copy should use a pool to allocate buffers.

@gopherbot
Copy link

Change https://go.dev/cl/456555 mentions this issue: io: allocate copy buffers from a pool

@neild neild self-assigned this Dec 9, 2022
@seankhliao seankhliao added this to the Backlog milestone Jan 20, 2023
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees

@neild neild

Labels
NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. Performance
Projects
None yet
Milestone
Backlog
Development

Successfully merging a pull request may close this issue.

net/http: use copyBufPool in transferWriter.doBodyCopy() mmatczuk/go
4 participants
@neild @mmatczuk @gopherbot @seankhliao