Re: x86 SHA1: Faster than OpenSSL

[Linus Torvalds <torvalds@linux-foundation.org>]

On Mon, 4 Aug 2009, George Spelvin wrote:
> 
> The actual goal of this effort is to address the dynamic linker startup
> time issues by removing the second-largest contributor after libcurl,
> namely openssl.  Optimizing the assembly code is just the fun part. ;-)

Now, I agree that it would be wonderful to get rid of the linker startup, 
but the startup costs of openssl are very low compared to the equivalent 
curl ones. So we can't lose _too_ much performance - especially for 
long-running jobs where startup costs really don't even matter - in the 
quest to get rid of those.

That said, your numbers are impressive. Improving fsck by 1.1-2.2% is very 
good. That means that you not only avodied the startup costs, you actually 
improved on the openssl code. So it's a win-win situation.

That said, it would be even better if the SHA1 code was also somewhat 
portable to other environments (it looks like your current patch is very 
GNU as specific), and if you had a solution for x86-64 too ;)

Yeah, I'm a whiny little b*tch, aren't I?

		Linus