Re: [PATCH] Implement limited context matching in git-apply.

From: Linus Torvalds <torvalds@osdl.org>
Date: Apr 10, 2006, 15:25 UTC
Message-ID: <Pine.LNX.4.64.0604100821340.9504@g5.osdl.org>
In-Reply-To: <m1irphhj1p.fsf_-_@ebiederm.dsl.xmission.com>

On Mon, 10 Apr 2006, Eric W. Biederman wrote:

Show 7 quoted lines

> 
> If I just loop through all of Andrews patches in order
> and run git-apply --index -C1 I process the entire patchset
> in 1m53s or about 6 patches per second.  So running
> git-mailinfo, git-write-tree, git-commit-tree, and
> git-update-ref everytime has a measurable impact,
> and shows things can be speeded up even more.

git-write-tree is actually a fairly expensive operation on the kernel. It needs to write the 1000+ tree objects - and while _most_ of them already exist (and thus don't actually need to be written out), we need to generate the tree object and its SHA1 in order to notice that that is the case.

I'm almost certain that 90%+ of the overhead you see is the tree writing, not the rest of the scripting.

Your patch looks ok from a quick read-through:

Acked-by: Linus Torvalds <torvalds@osdl.org>

		Linus