Re: [PATCH] Disable OpenSSL SHA1 implementation by default

On Mon, Feb 22, 2010 at 6:23 AM, Jeff King [off-list ref] wrote:

On Mon, Feb 22, 2010 at 05:08:14AM -0600, Jonathan Nieder wrote:

quoted

The OpenSSL SHA-1 routine is about as fast as block-sha1, but linking
to libcrypto slows down the startup of git commands by an appreciable
amount.  Use the BLK_SHA1 implementation by default instead.

What is your definition of "about as fast"? I benchmarked up to a 20%
slow-down a while back:

For what it's worth, here are my numbers from running git-fsck on my
x86-64 machine.  It appears that BLK-SHA1 is slightly faster.  If you
know a better benchmark to run, let me know.  Perhaps it would be good
to write some sort of suite to test this, and let people post their
results to some website.

make git-fsck
./git-fsck  66.75s user 0.28s system 99% cpu 1:07.17 total
./git-fsck  66.70s user 1.28s system 99% cpu 1:08.06 total
./git-fsck  66.77s user 0.63s system 99% cpu 1:07.42 total

make BLK_SHA1=1 git-fsck
./git-fsck  65.60s user 0.65s system 99% cpu 1:06.26 total
./git-fsck  65.39s user 0.65s system 99% cpu 1:06.06 total
./git-fsck  65.24s user 1.36s system 100% cpu 1:06.60 total

Core 2 Duo E6300 1.86 GHz (2MB L2 cache), 2GB memory
Ubuntu 9.10 x86-64, gcc 4.4.1, git v1.7.0-90-g251a495