Re: gc --aggressive

From: Jeff King <peff@peff.net>
Date: May 1, 2012, 17:16 UTC
Message-ID: <20120501171640.GA16623@sigill.intra.peff.net>
In-Reply-To: <20120501162806.GA15614@sigill.intra.peff.net>

On Tue, May 01, 2012 at 12:28:06PM -0400, Jeff King wrote:

> >  You could test this theory by commenting out the size comparisons in 
> > type_size_sort() and re-run the test.
> 
> I'll try this next.

Wow, it behaves horribly. I didn't even let the bigger tests run to completion. Here is the output for git.git (the first line is from the original, unmodified version of git with --window=10):

  orig | 31.4M (100%) |   54s (100%)
    10 | 44.0M (140%) |  169s (310%)
    20 | 37.7M (120%) |  232s (428%)
    40 | 33.6M (107%) |  331s (608%)
    80 | 30.9M ( 99%) |  473s (868%)
   160 | 29.4M ( 94%) |  696s (1279%)

Unless the window is increased a lot, the packs end up quite a bit larger (and even still we spend a lot more CPU time).

-Peff