From: Christopher Baines <mail@cbaines.net>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: guix-devel@gnu.org
Subject: Re: [PATCH] git-download: Speed up 'git-predicate'.
Date: Wed, 7 Jun 2017 19:12:38 +0100 [thread overview]
Message-ID: <a636fbd3-d6f1-8af9-7f7b-929dd3dbf262@cbaines.net> (raw)
In-Reply-To: <87fufc3r8w.fsf@gnu.org>
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On 07/06/17 13:40, Ludovic Courtès wrote:
> Hi Christopher,
>
> Christopher Baines <mail@cbaines.net> skribis:
>
>> Running the current implementation of git-predicate on the guix
>> repository with 50 trials takes:
>>
>> real 0m5.374s
>> user 0m4.052s
>> sys 0m1.484s
>>
>> Compared to the following for the patched implementation:
>>
>> real 0m8.398s
>> user 0m5.040s
>> sys 0m2.016s
>>
>> This shows that the patched implementation has decreased the
>> performance. Using the real value, the test time has increased by ~3
>> seconds. This corresponds roughly to a change from ~0.11 seconds
>> previously, to ~0.17 seconds for each individual traversal of the entire
>> repository.
>>
>> I encountered a performance issue when trying to use git-predicate with
>> this repository [2], which I have written a Guix package for here [3].
>> Instead of the 1463 files that git ls-files reports locally for the guix
>> repository, smart-answers contains 26732 files.
>>
>> The running time with smart-answers is left as an exercise to the
>> reader, all I can say is that on my machine, it takes more than 40
>> minutes for just 1 trial.
>>
>> Using this patch, running the test script with 1 trial gives:
>>
>> real 0m4.917s
>> user 0m3.640s
>> sys 0m1.428s
>
> So in short, the new implementation is 100 times faster on large repos
> but roughly the same or slightly slower on smaller repos, right?
Yep, that's right :)
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next prev parent reply other threads:[~2017-06-07 18:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-02 7:08 [PATCH] git-download: Speed up 'git-predicate' Christopher Baines
2017-06-02 7:34 ` Christopher Baines
2017-06-07 12:40 ` Ludovic Courtès
2017-06-07 18:12 ` Christopher Baines [this message]
2017-06-07 12:52 ` Ludovic Courtès
2017-06-08 20:43 ` Christopher Baines
2017-06-19 7:14 ` Christopher Baines
2017-06-21 21:44 ` Ludovic Courtès
2017-07-16 10:42 ` Christopher Baines
2017-07-25 21:26 ` Ludovic Courtès
2017-07-26 9:58 ` Christopher Baines
2017-06-19 7:24 ` Christopher Baines
2017-06-21 21:17 ` Ludovic Courtès
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