From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@jeffhostetler.com, git@vger.kernel.org,
Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH v1] diffcore-rename: speed up register_rename_src
Date: Tue, 18 Apr 2017 19:45:05 -0700 [thread overview]
Message-ID: <xmqqd1c9cdzi.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170419013214.q35jarvmk5jhqdyi@sigill.intra.peff.net> (Jeff King's message of "Tue, 18 Apr 2017 21:32:15 -0400")
Jeff King <peff@peff.net> writes:
> On Tue, Apr 18, 2017 at 07:44:21PM +0000, git@jeffhostetler.com wrote:
>
>> From: Jeff Hostetler <jeffhost@microsoft.com>
>>
>> Teach register_rename_src() to see if new file pair
>> can simply be appended to the rename_src[] array before
>> performing the binary search to find the proper insertion
>> point.
>
> I guess your perf results show some minor improvement. But I suspect
> this is because your synthetic repo does not resemble the real world
> very much. You're saving a few strcmps, but for each of those files
> you're potentially going to have actually zlib inflate the object
> contents and do similarity analysis.
>
> So "absurd number of files doing 100% exact renames" is the absolute
> best case, and it saves a few percent.
>
> I dunno. It is not that much code _here_, but I'm not excited about the
> prospect of sprinkling this same "check the last one" optimization all
> over the code base. I wonder if there's some way to generalize it.
When adding many things, we often just append and then sort at the
end after we finished adding. I wonder if recent "check the last
one and append" optimization beats that strategy.
next prev parent reply other threads:[~2017-04-19 2:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-18 19:44 [PATCH v1] diffcore-rename speedup git
2017-04-18 19:44 ` [PATCH v1] diffcore-rename: speed up register_rename_src git
2017-04-19 1:32 ` Jeff King
2017-04-19 2:45 ` Junio C Hamano [this message]
2017-04-19 2:56 ` Jeff King
2017-04-19 3:18 ` Jeff King
2017-04-20 14:00 ` Jeff Hostetler
2017-04-20 16:13 ` Jeff King
2017-04-20 18:08 ` Jeff Hostetler
2017-04-20 18:34 ` Jeff King
2017-04-21 1:19 ` Junio C Hamano
2017-04-20 10:40 ` Johannes Schindelin
2017-04-20 15:50 ` Jeff King
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