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From: Shawn Pearce <spearce@spearce.org>
To: Colby Ranger <cranger@google.com>
Cc: "Jeff King" <peff@peff.net>, "Vicent Martí" <tanoku@gmail.com>,
	git <git@vger.kernel.org>
Subject: Re: [PATCH 09/16] documentation: add documentation for the bitmap format
Date: Wed, 26 Jun 2013 19:32:21 -0600	[thread overview]
Message-ID: <CAJo=hJuA_4zL-cyygqPkDA+6ipbTqsmMYHw-c6OTKCcb5GAs0g@mail.gmail.com> (raw)
In-Reply-To: <CAFFbUKJTh79-u-D89OAZxjCnfvyZ40DE_iwQ6e+zXSw88AY6PQ@mail.gmail.com>

On Wed, Jun 26, 2013 at 6:53 PM, Colby Ranger <cranger@google.com> wrote:
>> +  Generating this reverse index at runtime is **not** free (around 900ms
>> +  generation time for a repository like `torvalds/linux`), and once again,
>> +  this generation time needs to happen every time `pack-objects` is
>> +  spawned.

900ms is fishy. Creating the revidx should not take that long. But if it is...

> If generating the reverse index is expensive, it is probably
> worthwhile to create a ".revidx" or extend the ".idx" with the
> information sorted by offset.

Colby is probably right that a cached copy of the revidx would help.
Or update the .idx format to have two additional sections that stores
the length of each packed object and the delta base of each packed
object, allowing pack-objects to avoid creating the revidx. This would
be an additional ~8 bytes per object, so ~19.8M for the Linux kernel
(given ~2.6M objects).

  reply	other threads:[~2013-06-27  1:32 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 [this message]
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
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

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