Re: Why Git is so fast (was: Re: Eric Sink's blog - notes on git, dscms and a "whole product" approach)

From: Jeff King <peff@peff.net>
Date: May 1, 2009, 19:08 UTC
Message-ID: <20090501190854.GA13770@coredump.intra.peff.net>
In-Reply-To: <alpine.LFD.2.00.0905011431460.5379@localhost.localdomain>

On Fri, May 01, 2009 at 02:43:49PM -0400, Linus Torvalds wrote:

Show 11 quoted lines

> > Like all generalizations, this is only mostly true. Fast network servers
> > with big caches can outperform disks for some loads.
> [...]
> In contrast, a workstation with local filesystems and enough memory to 
> cache it well will just be a lot nicer.
> [...]
> > I have never used perforce, but I get the impression that it is more 
> > optimized for such a situation.
> 
> I doubt it. I suspect git will outperform pretty much anything else in 
> that kind of situation too.

Thanks for the analysis; what you said makes sense to me. However, there is at least one case of somebody complaining that git doesn't scale as well as perforce for their load:

  http://gandolf.homelinux.org/blog/index.php?id=50

Part of his issue is with git-p4 sucking, which it probably does. But part of it sounds like he has a gigantic workload (the description of which sounds silly to me, but I respect the fact that he is probably describing standard practice among some companies), and that workload is just a little too gigantic for the workstations to handle. I.e., by throwing resources at the central server they can avoid throwing as many at each workstation.

But there are so few details it's hard to say whether he's doing something else wrong or suboptimally. He does mention Windows, which IIRC has horrific stat performance.

-Peff