crypto/rsa: linux/arm64 Go 1.9 performance is +10X slower than OpenSSL

[williamweixiao]

Please answer these questions before submitting your issue. Thanks!

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

go version go1.9.2 linux/arm64

Does this issue reproduce with the latest release?

yes

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

GOARCH="arm64"
GOBIN=""
GOEXE=""
GOHOSTARCH="arm64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH=""
GORACE=""
GOROOT="/usr/lib/go-1.6"
GOTOOLDIR="/usr/lib/go-1.6/pkg/tool/linux_arm64"
GO15VENDOREXPERIMENT="1"
CC="gcc"
GOGCCFLAGS="-fPIC -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

What did you do?

go test crypto/rsa -bench .

What did you expect to see?

Performance can be on par with OpenSSL (https://blog.cloudflare.com/content/images/2017/11/pub_key_1_core-2.png)

What did you see instead?

+10X slower than OpenSSL (https://blog.cloudflare.com/content/images/2017/11/go_pub_key_1_core.png)

[vielmetti]

Go 1.11beta1 is substantially faster than Go 1.10.2 on this test, on Cavium ThunderX / Packet c1.large.arm ("Type 2A").

ed@ed-2a-bcc-llvm:~$ go version
go version go1.10.2 linux/arm64
ed@ed-2a-bcc-llvm:~$ go test crypto/rsa -bench .
goos: linux
goarch: arm64
pkg: crypto/rsa
BenchmarkRSA2048Decrypt-96                    20          74651551 ns/op
BenchmarkRSA2048Sign-96                       20          77650290 ns/op
Benchmark3PrimeRSA2048Decrypt-96              50          35958813 ns/op
PASS
ok      crypto/rsa      8.809s
ed@ed-2a-bcc-llvm:~$ ~/go/bin/go1.11beta1 test crypto/rsa -bench .
goos: linux
goarch: arm64
pkg: crypto/rsa
BenchmarkRSA2048Decrypt-96                   100          11466566 ns/op
BenchmarkRSA2048Sign-96                      100          11855513 ns/op
Benchmark3PrimeRSA2048Decrypt-96             200           7684199 ns/op
PASS
ok      crypto/rsa      6.584s