net/http: http/2 throughput is very slow compared to http/1.1

[kgersen]

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

1.7

$ go version
go version go1.17 linux/amd64

Does this issue reproduce with the latest release?

yes

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

Linux, Windows, etc

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/user/.cache/go-build"
GOENV="/home/user/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/user/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/user/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.17"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/user/dev/http2issue/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build38525640=/tmp/go-build -gno-record-gcc-switches"

What did you do?

test http/2 vs http1.1 transfert speed with client and server from standard lib

see a complete POC here: https://github.com/nspeed-app/http2issue

The issue is general, loopback (localhost) or over the wire.

What did you expect to see?

same speed order than http1.1

What did you see instead?

http/2 is at least x5 slower or worst

[neild]

You're comparing encrypted HTTP/2 with unencrypted HTTP. You need to compare HTTP/2 with HTTPS to compare like with like.

[kgersen]

hi, the POC is using H2C to avoid encryption.
I also compared encrypted versions with the product we're developing and we have the same issue.

[kgersen]

Caddy a web server written in Go has the same issue. I've updated the POC with a sample Caddy config: https://github.com/nspeed-app/http2issue/tree/main/3rd-party/Caddy