From: "Vicent Martí" <tanoku@gmail.com>
To: Thomas Rast <trast@inf.ethz.ch>
Cc: git <git@vger.kernel.org>
Subject: Re: [PATCH 11/16] rev-list: add bitmap mode to speed up lists
Date: Wed, 26 Jun 2013 03:45:26 +0200 [thread overview]
Message-ID: <CAFFjANSYoRGFDx109kMWJtYAO4TaTwSW0NCaemnrERuwakfpGg@mail.gmail.com> (raw)
In-Reply-To: <87mwqdlvsq.fsf@linux-k42r.v.cablecom.net>
I'm afraid I cannot reproduce the segfault locally (assuming you're
performing the rev-list on the git/git repository). Could you please
send me more information, and a core dump if possible?
On Tue, Jun 25, 2013 at 6:22 PM, Thomas Rast <trast@inf.ethz.ch> wrote:
> Vicent Marti <tanoku@gmail.com> writes:
>
>> Calling `git rev-list --use-bitmaps [committish]` is the equivalent
>> of `git rev-list --objects`, but the rev list is performed based on
>> a bitmap result instead of using a manual counting objects phase.
>
> Why would we ever want to not --use-bitmaps, once it actually works?
> I.e., shouldn't this be the default if pack.usebitmaps is set (or
> possibly even core.usebitmaps for these things)?
>
>> These are some example timings for `torvalds/linux`:
>>
>> $ time ../git/git rev-list --objects master > /dev/null
>>
>> real 0m25.567s
>> user 0m25.148s
>> sys 0m0.384s
>>
>> $ time ../git/git rev-list --use-bitmaps master > /dev/null
>>
>> real 0m0.393s
>> user 0m0.356s
>> sys 0m0.036s
>
> I see your badass numbers, and raise you a critical issue:
>
> $ time git rev-list --use-bitmaps --count --left-right origin/pu...origin/next
> Segmentation fault
>
> real 0m0.408s
> user 0m0.383s
> sys 0m0.022s
>
> It actually seems to be related solely to having negated commits in the
> walk:
>
> thomas@linux-k42r:~/g(next u+65)$ time git rev-list --use-bitmaps --count origin/pu
> 32315
>
> real 0m0.041s
> user 0m0.034s
> sys 0m0.006s
> thomas@linux-k42r:~/g(next u+65)$ time git rev-list --use-bitmaps --count origin/pu ^origin/next
> Segmentation fault
>
> real 0m0.460s
> user 0m0.214s
> sys 0m0.244s
>
> I also can't help noticing that the time spent generating the segfault
> would have sufficed to generate the answer "the old way" as well:
>
> $ time git rev-list --count --left-right origin/pu...origin/next
> 189 125
>
> real 0m0.409s
> user 0m0.386s
> sys 0m0.022s
>
> Can we use the same trick to speed up merge base computation and then
> --left-right? The latter is a component of __git_ps1 and can get
> somewhat slow in some cases, so it would be nice to make it really fast,
> too.
>
> --
> Thomas Rast
> trast@{inf,student}.ethz.ch
next prev parent reply other threads:[~2013-06-26 1:45 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-24 23:22 [PATCH 00/16] Speed up Counting Objects with bitmap data Vicent Marti
2013-06-24 23:22 ` [PATCH 01/16] list-objects: mark tree as unparsed when we free its buffer Vicent Marti
2013-06-24 23:22 ` [PATCH 02/16] sha1_file: refactor into `find_pack_object_pos` Vicent Marti
2013-06-25 13:59 ` Thomas Rast
2013-06-24 23:23 ` [PATCH 03/16] pack-objects: use a faster hash table Vicent Marti
2013-06-25 14:03 ` Thomas Rast
2013-06-26 2:14 ` Jeff King
2013-06-26 4:47 ` Jeff King
2013-06-25 17:58 ` Ramkumar Ramachandra
2013-06-25 22:48 ` Junio C Hamano
2013-06-25 23:09 ` Vicent Martí
2013-06-24 23:23 ` [PATCH 04/16] pack-objects: make `pack_name_hash` global Vicent Marti
2013-06-24 23:23 ` [PATCH 05/16] revision: allow setting custom limiter function Vicent Marti
2013-06-24 23:23 ` [PATCH 06/16] sha1_file: export `git_open_noatime` Vicent Marti
2013-06-24 23:23 ` [PATCH 07/16] compat: add endinanness helpers Vicent Marti
2013-06-25 13:08 ` Peter Krefting
2013-06-25 13:25 ` Vicent Martí
2013-06-27 5:56 ` Peter Krefting
2013-06-24 23:23 ` [PATCH 08/16] ewah: compressed bitmap implementation Vicent Marti
2013-06-25 1:10 ` Junio C Hamano
2013-06-25 22:51 ` Junio C Hamano
2013-06-25 15:38 ` Thomas Rast
2013-06-24 23:23 ` [PATCH 09/16] documentation: add documentation for the bitmap format Vicent Marti
2013-06-25 5:42 ` Shawn Pearce
2013-06-25 19:33 ` Vicent Martí
2013-06-25 21:17 ` Junio C Hamano
2013-06-25 22:08 ` Vicent Martí
2013-06-27 1:11 ` Shawn Pearce
2013-06-27 2:36 ` Vicent Martí
2013-06-27 2:45 ` Jeff King
2013-06-27 16:07 ` Shawn Pearce
2013-06-27 17:17 ` Jeff King
2013-07-01 18:47 ` Colby Ranger
2013-07-01 19:13 ` Shawn Pearce
2013-07-07 9:46 ` Jeff King
2013-07-07 17:27 ` Shawn Pearce
2013-06-26 5:11 ` Jeff King
2013-06-26 18:41 ` Colby Ranger
2013-06-26 22:33 ` Colby Ranger
2013-06-27 0:53 ` Colby Ranger
2013-06-27 1:32 ` Shawn Pearce
2013-06-27 1:29 ` Shawn Pearce
2013-06-25 15:58 ` Thomas Rast
2013-06-25 22:30 ` Vicent Martí
2013-06-26 23:12 ` Thomas Rast
2013-06-26 23:19 ` Thomas Rast
2013-06-24 23:23 ` [PATCH 10/16] pack-objects: use bitmaps when packing objects Vicent Marti
2013-06-25 12:48 ` Ramkumar Ramachandra
2013-06-25 15:58 ` Thomas Rast
2013-06-25 23:06 ` Junio C Hamano
2013-06-25 23:14 ` Vicent Martí
2013-06-24 23:23 ` [PATCH 11/16] rev-list: add bitmap mode to speed up lists Vicent Marti
2013-06-25 16:22 ` Thomas Rast
2013-06-26 1:45 ` Vicent Martí [this message]
2013-06-26 23:13 ` Thomas Rast
2013-06-26 5:22 ` Jeff King
2013-06-24 23:23 ` [PATCH 12/16] pack-objects: implement bitmap writing Vicent Marti
2013-06-24 23:23 ` [PATCH 13/16] repack: consider bitmaps when performing repacks Vicent Marti
2013-06-25 23:00 ` Junio C Hamano
2013-06-25 23:16 ` Vicent Martí
2013-06-24 23:23 ` [PATCH 14/16] sha1_file: implement `nth_packed_object_info` Vicent Marti
2013-06-24 23:23 ` [PATCH 15/16] write-bitmap: implement new git command to write bitmaps Vicent Marti
2013-06-24 23:23 ` [PATCH 16/16] rev-list: Optimize --count using bitmaps too Vicent Marti
2013-06-25 16:05 ` [PATCH 00/16] Speed up Counting Objects with bitmap data Thomas Rast
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAFFjANSYoRGFDx109kMWJtYAO4TaTwSW0NCaemnrERuwakfpGg@mail.gmail.com \
--to=tanoku@gmail.com \
--cc=git@vger.kernel.org \
--cc=trast@inf.ethz.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).