Re: Some git performance measurements..

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Nov 29, 2007, 17:48 UTC
Message-ID: <alpine.LFD.0.9999.0711290945060.8458@woody.linux-foundation.org>
In-Reply-To: <alpine.LFD.0.99999.0711291208060.9605@xanadu.home>

On Thu, 29 Nov 2007, Nicolas Pitre wrote:

> 
> Well, see below for the patch that actually split the pack data into 
> objects of the same type.  Doing that "git checkout" on the kernel tree 
> did improve things for me although not spectacularly.

Umm. See my earlier numbers. For "git checkout" with cold cache, the *bulk* of the time is actually the ".gitignore" file lookups, so if you see a three-second improvement out of 17s, it may not look spectacular, but considering that probably 10s of those 17s were something *else* going on, I suspect that if you really did just a plain "git checkout", you actually *do* have a spectacular improvement of roughly 7s -> 4s!

Try with

	time git read-tree -m -u HEAD HEAD > /dev/null

instead.

But if that is what you already did, then yeah, the performance improvement for cold-cache wasn't as big as I was hoping for.

		Linus