From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 09 Sep 2011 21:00:29 GMT
Subject: Re: [PATCH] fetch: skip on-demand checking when no submodules are configured
Message-ID: <7vaaadtor6.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4E6A594B.9030108@web.de>

Jens Lehmann <Jens.Lehmann@web.de> writes:

> It makes no sense to do the - possibly very expensive - call to "rev-list
> <new-ref-sha1> --not --all" in check_for_new_submodule_commits() when
> there aren't any submodules configured.
>
> Leave check_for_new_submodule_commits() early when no name <-> path
> mappings for submodules are found in the configuration. To make that work
> reading the configuration had to be moved further up in cmd_fetch(), as
> doing that after the actual fetch of the superproject was too late.
>
> Reported-by: Martin Fick <mfick@codeaurora.org>
> Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
> ---
>
> This achieves the first goal: Don't let people pay a performance penalty
> when they don't even use submodules. On Michael's test repo from [1] the
> time for a full fetch went down from 142 seconds (current master) to one
> second which is - not surprisingly - the same as using current master
> with the --no-recurse-submodules option.
>
> Now back to the drawing board to fix the performance regression for those
> people who are using submodules ...
>
> [1] http://comments.gmane.org/gmane.comp.version-control.git/177103

Thanks.