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From: Derrick Stolee <stolee@gmail.com>
To: Peter Krefting <peter@softwolves.pp.se>, Jeff King <peff@peff.net>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: cherry-pick very slow on big repository
Date: Fri, 10 Nov 2017 07:59:55 -0500	[thread overview]
Message-ID: <7e242038-50e5-2cfc-e810-401af78b8cdc@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1711101333030.2391@ds9.cixit.se>

On 11/10/2017 7:37 AM, Peter Krefting wrote:
> Jeff King:
>
>> Can you get a backtrace? I'd do something like:
>
> Seems that it spends most time in diffcore_count_changes(), that is 
> where it hits whenever I hit Ctrl+C (various line numbers 199-207 in 
> diffcore-delta.c; this is on the v2.15.0 tag).
>
> (gdb) bt
> #0  diffcore_count_changes (src=src@entry=0x55555db99970,
>     dst=dst@entry=0x55555d6a4810,
>     src_count_p=src_count_p@entry=0x55555db99998,
>     dst_count_p=dst_count_p@entry=0x55555d6a4838,
>     src_copied=src_copied@entry=0x7fffffffd3e0,
>     literal_added=literal_added@entry=0x7fffffffd3f0)
>     at diffcore-delta.c:203
> #1  0x00005555556dee1a in estimate_similarity (minimum_score=30000,
>     dst=0x55555d6a4810, src=0x55555db99970) at diffcore-rename.c:193
> #2  diffcore_rename (options=options@entry=0x7fffffffd4f0)
>     at diffcore-rename.c:560
> #3  0x0000555555623d83 in diffcore_std (
>     options=options@entry=0x7fffffffd4f0) at diff.c:5846
> ...

Git is spending time detecting renames, which implies you probably 
renamed a folder or added and deleted a large number of files. This 
rename detection is quadratic (# adds times # deletes).

You can remove this rename detection by running your cherry-pick with 
`git -c diff.renameLimit=1 cherry-pick ...`

See https://git-scm.com/docs/diff-config#diff-config-diffrenameLimit

Thanks,
-Stolee

  reply	other threads:[~2017-11-10 13:00 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10  9:39 cherry-pick very slow on big repository Peter Krefting
2017-11-10 10:20 ` Jeff King
2017-11-10 12:37   ` Peter Krefting
2017-11-10 12:59     ` Derrick Stolee [this message]
2017-11-10 14:05       ` Peter Krefting
2017-11-10 17:04         ` Kevin Willford
2017-11-13 11:19           ` Peter Krefting
2017-11-10 17:37         ` Elijah Newren
2017-11-10 23:32         ` Elijah Newren
2017-11-13 11:22           ` Peter Krefting
2017-11-13 18:09             ` Elijah Newren
2017-11-21 12:07               ` Peter Krefting
2017-11-21 17:14                 ` Elijah Newren

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