From: Colby Ranger <cranger@google.com>
Date: Mon, 01 Jul 2013 18:47:32 GMT
Subject: Re: [PATCH 09/16] documentation: add documentation for the bitmap format
Message-ID: <CAFFbUKKm89n0HG6xUhYMLs_yjRJ8n0jFtOEEN=vXxJfWKLx5FA@mail.gmail.com>
In-Reply-To: <CAJo=hJvOq=CATrDeYAwi+jgkPpqjywWhuKeC1TVYeCXr6NVM6w@mail.gmail.com>

> Right, the format and implementation in JGit can do "Counting objects"
> in 87ms for the Linux kernel history.

Actually, that was the timing when I first pushed the change. With the
improvements submitted throughout the year, we can do counting in
50ms, on my same machine.

> But I think we are comparing
> apples to steaks here, Vincent is (rightfully) concerned about process
> startup performance, whereas our timings were assuming the process was
> already running.
>

I did some timing on loading the reverse index for the kernel and it
is pretty slow (~1200ms). I just submitted a fix to do a bucket sort
and reduced that to ~450ms, which is still slow but much better:
https://eclipse.googlesource.com/jgit/jgit/+/6cc532a43cf28403cb623d3df8600a2542a40a43%5E%21/