From: Dana How <danahow@gmail.com>
Date: Tue, 08 May 2007 17:07:44 GMT
Subject: Re: [PATCH] Add pack.depth option to git-pack-objects and change default depth to 50
Message-ID: <56b7f5510705081007v4840ff7cma754a75eb3d3377f@mail.gmail.com>
In-Reply-To: <20070508163044.GA15796@thunk.org>

On 5/8/07, Theodore Tso <tytso@mit.edu> wrote:
> The following results are on a recent git repository, using time to
> record the real, user, and sys times on the two commands: "git-gc
> --no-reuse-delta --window=X --depth=Y" and "git log --pretty=oneline
> -S'object' > /dev/null".  All of these tests were done with a hot
> cache, so disk speed didn't enter into the calculations.
>
> ...
>
> So a couple of things immediately become evident.  First of all, as
> Junio predicted, changing --depth makes no difference to the git-gc or
> git log times.  The latter is thanks to the delta chaching.  Secondly,
> changing --depth does make a signficiant difference to the pack size.
>
> Finally, --window does help somewhat in reducing the pack size, but it
> _significantly_ increases the time to calculate the pack.
>
> My conclusion given this quick benchmark is that it seems to me that
> changing the defaults of --depth to 50, and keeping --window at 10, is
> a reasonable thing to do.

If you still have the packfiles around,  the times for some non-pickaxe
git-log commands would be interesting,  like from git-log's man page:
       git log v2.6.12.. include/scsi drivers/scsi
       git log --since="2 weeks ago" -- gitk
These operations would be more dominated by processing smaller objects.

Thanks,
-- 
Dana L. How  danahow@gmail.com  +1 650 804 5991 cell