Re: Debugging git-commit slowness on a large repo

[Joshua Redstone <joshua.redstone@fb.com>]

I looked again at my poor-mans-profiling output of git-add.  The Sha1
stuff under ce_write_entry->ce_write_flush  takes a bunch of time.
commit_lock_file->rename takes about the same as well.

Btw, the perf numbers for commit and add are with a warm file cache.  I
expect the benefit of skipping all the stat() calls will increase for cold
cache.

Josh

On 12/20/11 1:23 AM, "Thomas Rast" <trast@student.ethz.ch> wrote:

>Joshua Redstone <joshua.redstone@fb.com> writes:
>> As a bonus, I've also profiled git-add on the 1-million file repo, and
>>it
>> looks like, as you might expect, the time is dominated by reading and
>> writing the index.  The time for git-add is a couple of seconds.
>
>Note that the time to write the index itself is also rather small, but
>the time needed to sha1 the index when loading and then again when
>saving it really hurts.
>
>(I noticed this while working on the commit-tree topic.)
>
>-- 
>Thomas Rast
>trast@{inf,student}.ethz.ch