Re: code review 28460043: crypto/sha256: block implementation in amd64 assembly (issue 28460043)

[js...@google.com]

On 2013/12/02 17:56:25, agl1 wrote:
> LGTM with nits.

> Just to confirm - the addition of |s| to |digest| is just to avoid
stack
> allocation in the block function, right?

Correct. I've reworked it so that we use stack-based allocation (which
means we have to enable stack splitting) - this resolves your other
dislike and seems to give a small performance gain.


https://codereview.appspot.com/28460043/diff/60001/src/pkg/crypto/sha256/sha256.go
> File src/pkg/crypto/sha256/sha256.go (right):


https://codereview.appspot.com/28460043/diff/60001/src/pkg/crypto/sha256/sha256.go#newcode49
> src/pkg/crypto/sha256/sha256.go:49: type schedule struct {
> The use of a new type for this seems excessive.

PTAL

https://codereview.appspot.com/28460043/

[a...@golang.org]

*** Submitted as
https://code.google.com/p/go/source/detail?r=5de0f8743adf ***

crypto/sha256: block implementation in amd64 assembly

Benchmark on Intel(R) Xeon(R) CPU X5650  @ 2.67GHz

benchmark old ns/op new ns/op delta
BenchmarkHash8Bytes 1259 677 -46.23%
BenchmarkHash1K 14387 6749 -53.09%
BenchmarkHash8K 106006 50107 -52.73%

benchmark old MB/s new MB/s speedup
BenchmarkHash8Bytes 6.35 11.81 1.86x
BenchmarkHash1K 71.17 151.72 2.13x
BenchmarkHash8K 77.28 163.49 2.12x

R=agl
CC=golang-dev
https://codereview.appspot.com/28460043

Committer: Adam Langley <a...@golang.org>


https://codereview.appspot.com/28460043/

[Donovan Hide]

Hi,

are they any plans for giving the same treatment to SHA512? The proof of work algorithm for Ripple uses an unusual hash that involves taking the first 32 bytes of a SHA512 hash. Would be great if we could get similar speedups :-)

https://ripple.com/wiki/Proof_of_Work

All the best,

Donovan.

https://codereview.appspot.com/28460043/

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[Joel Sing]

I had planned on looking at it, but it was low on my list of priorities... however, since you asked :)

https://codereview.appspot.com/37150044

[Donovan Hide]

Wow, that looks extremely good to me :-)

Thank you very, very much! I'm contacting the Guinness Books to ask them to record the fastest delivery of an assembly version of a crypto hasher!

Cheers,

Donovan (busy proving work!)