Re: x86 SHA1: Faster than OpenSSL

From: George Spelvin <linux@horizon.com>
Date: Aug 5, 2009, 18:17 UTC
Message-ID: <20090805181755.22765.qmail@science.horizon.com>
In-Reply-To: <7vljlzjorh.fsf@alter.siamese.dyndns.org>

Show 14 quoted lines

> Three classes of people compile git from the source:
>
> * People who want to be on the bleeding edge and compile git for
>   themselves, even though they are on mainstream platforms where they
>   could choose distro-packaged one;
>
> * People who produce binary packages for distribution.
>
> * People who are on minority platforms and have no other way to get git
>   than compiling for themselves;
>
> We do not have to worry about the first two groups of people.  It won't
> be too involved for them to install Perl on their system; after all they
> are already coping with asciidoc and xmlto ;-)

Actually, I'd get rid of the perl entirely, but I'm not sure how necessary the other-assembler-syntax features are needed by the folks on MacOS X and Windows (msysgit).

> We can continue shipping mozilla one to help the last group.

Of course, we always need a C fallback.  Would you like a faster one?

Show 7 quoted lines

> In the Makefile, we say:
>
>    # Define NO_OPENSSL environment variable if you do not have OpenSSL.
>    # This also implies MOZILLA_SHA1.
>
> and with your change, we would start implying STANDALONE_OPENSSL_SHA1
> instead.  But if MOZILLA_SHA1 was given explicitly, we could use that.

Well, I'd really like to auto-detect the processor. Current gcc's "gcc -v" output includes a "Target: " line that will do nicely. I can, of course, fall back to C if it fails, but is there a significant user base using a non-GCC compiler?