Re: 'git gc --aggressive' effectively unusable

From: Jeff King <peff@peff.net>
Date: Apr 4, 2010, 21:49 UTC
Message-ID: <20100404214944.GA15104@coredump.intra.peff.net>
In-Reply-To: <20100404203850.GA8798@coredump.intra.peff.net>

On Sun, Apr 04, 2010 at 04:38:50PM -0400, Jeff King wrote:

Show 15 quoted lines

> I packed Frans' sample kernel repo with "git gc --aggressive" last
> night. It did finish after about 9 hours. I didn't take memory usage
> measurements, but here's what time said:
> 
>   real    535m38.898s
>   user    216m46.437s
>   sys     0m24.186s
> 
> That's 3.6 hours of CPU time over almost 9 hours (on a dual-core
> machine). The non-agressive pack was about 680M, and the result was
> 480M. The machine has 2G of RAM, and not much else running. So I would
> really not expect there to be much disk I/O required, but clearly we
> were waiting quite a bit.
> 
> I'll try tweaking a few of the pack memory limits and try again.

Hmm, this may be relevant:

  http://thread.gmane.org/gmane.comp.version-control.git/67791/focus=94797

In my experiments, memory usage is increasing but valgrind doesn't leaks. So perhaps it is fragmentation in the memory allocator.

-Peff