From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Taylor Blau <me@ttaylorr.com>,
git@vger.kernel.org, dstolee@microsoft.com
Subject: Re: [PATCH 0/1] commit-graph: avoid unnecessary tag deference when merging
Date: Sat, 21 Mar 2020 01:04:55 -0400 [thread overview]
Message-ID: <20200321050455.GB1438317@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqo8sq9uhb.fsf@gitster.c.googlers.com>
On Fri, Mar 20, 2020 at 09:56:16PM -0700, Junio C Hamano wrote:
> Taylor Blau <me@ttaylorr.com> writes:
>
> > This patch avoids an unnecessary tag dereference in
> > 'merge_commit_graph()', which can improve the running time of a
> > commit-graph write by around ~7.4% on average.
>
> That I suspect depends heavily on what portion of your total
> committishes consist of tags, no (in an absurdly extreme case, if
> there is no tag in the repository, there won't be any improvement)?
>
> What tag-vs-commit ratio is the above "average" number based on?
I think the point is that in this code path we've already identified the
candidates as commits (because they were in an existing commit-graph
file), so treating the items as a committishes in the first place is
unnecessary. If an object isn't itself a commit, we should be dropping
it from the proposed output (possibly we ought to give a warning in such
a case, too, as it indicates the previous writer did something wrong).
-Peff
next prev parent reply other threads:[~2020-03-21 5:04 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-21 3:44 [PATCH 0/1] commit-graph: avoid unnecessary tag deference when merging Taylor Blau
2020-03-21 3:44 ` [PATCH 1/1] commit-graph.c: avoid unnecessary tag dereference " Taylor Blau
2020-03-21 5:00 ` Jeff King
2020-03-21 6:11 ` Taylor Blau
2020-03-21 6:24 ` Taylor Blau
2020-03-21 7:03 ` Jeff King
2020-03-21 17:27 ` Taylor Blau
2020-03-22 5:36 ` Jeff King
2020-03-22 11:04 ` SZEDER Gábor
2020-03-22 18:45 ` looking up object types quickly, was " Jeff King
2020-03-22 19:18 ` Jeff King
2020-03-23 20:15 ` Taylor Blau
2020-03-22 16:45 ` Taylor Blau
2020-03-24 6:06 ` Jeff King
2020-03-21 18:50 ` Junio C Hamano
2020-03-22 0:03 ` Derrick Stolee
2020-03-22 0:20 ` Taylor Blau
2020-03-22 0:23 ` Derrick Stolee
2020-03-22 5:49 ` Jeff King
2020-03-22 6:04 ` Jeff King
2020-03-22 15:47 ` Taylor Blau
2020-03-24 6:11 ` Jeff King
2020-03-24 23:08 ` Taylor Blau
2020-03-27 8:42 ` Jeff King
2020-03-27 15:03 ` Taylor Blau
2020-03-22 15:44 ` Taylor Blau
2020-03-24 6:14 ` Jeff King
2020-03-21 5:01 ` Junio C Hamano
2020-03-21 4:56 ` [PATCH 0/1] commit-graph: avoid unnecessary tag deference " Junio C Hamano
2020-03-21 5:04 ` Jeff King [this message]
2020-03-21 6:12 ` Taylor Blau
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