From: David Barr <davidbarr@google.com>
Date: Wed, 04 Apr 2012 01:44:24 GMT
Subject: Re: [PATCH 0/9] Prefix-compress on-disk index entries
Message-ID: <CAFfmPPOqb8Kn-LERyiLKL838DKw=X6=CTV1x0s8coPgAvNLUdw@mail.gmail.com>
In-Reply-To: <1333493596-14202-1-git-send-email-gitster@pobox.com>

On Wed, Apr 4, 2012 at 8:53 AM, Junio C Hamano <gitster@pobox.com> wrote:
> This is still rough, but with this patch I am getting:
>
>    $ ls -l .git/index*
>    -rw-r----- 1 jch eng 25586488 2012-04-03 15:27 .git/index
>    -rw-r----- 1 jch eng 14654328 2012-04-03 15:38 .git/index-4
>
> in a clone of WebKit repository that has 183175 paths.
>
> With hot-cache with no local modification:
>
>    $ time sh -c 'GIT_INDEX_FILE=.git/index-4 git diff'
>    real  0m0.469s
>    user  0m0.130s
>    sys   0m0.330s
>
>    $ time sh -c 'git diff'
>    real  0m0.677s
>    user  0m0.290s
>    sys   0m0.370s
>
> which is mesuring the time needed to read of the index into in-core
> structure and comparing the cached stat information taken from lstat(2).
>
> The updated format is not documented yet, as I didn't intend (and I still
> am not committed) to declare a change along this line the official "v4"
> format; I was merely being curious to see how much improvements we can get
> from a trivial approach like this.

As I am hacking on WebKit daily, I'll try out this series and give feedback.

--
David Barr