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From: Jeff King <peff@peff.net>
To: Christian Couder <christian.couder@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Christian Couder <chriscool@tuxfamily.org>,
	Ramsay Jones <ramsay@ramsayjones.plus.com>,
	Jonathan Tan <jonathantanmy@google.com>
Subject: Re: [PATCH v3 7/9] pack-objects: introduce pack.allowPackReuse
Date: Mon, 9 Dec 2019 02:14:12 -0500	[thread overview]
Message-ID: <20191209071412.GG40570@coredump.intra.peff.net> (raw)
In-Reply-To: <20191115141541.11149-8-chriscool@tuxfamily.org>

On Fri, Nov 15, 2019 at 03:15:39PM +0100, Christian Couder wrote:

> From: Jeff King <peff@peff.net>
> 
> Let's make it possible to configure if we want pack reuse or not.

...because? :)

I mostly used it for debugging and performance testing. I don't think
there should be any big downside to using it that would cause people to
want to turn it off. But it _might_ cause larger packs, because we
wouldn't consider the reused objects as bases for finding new deltas.

I think the documentation could mention this. And maybe make it a bit
more clear what "reuse" means.

So maybe:

diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 58323a351f..0dac580581 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -28,8 +28,11 @@ all existing objects. You can force recompression by passing the -F option
 to linkgit:git-repack[1].
 
 pack.allowPackReuse::
-	When true, which is the default, Git will try to reuse parts
-	of existing packfiles when preparing new packfiles.
+	When true, and when reachability bitmaps are enabled,
+	pack-objects will try to send parts of the bitmapped packfile
+	verbatim. This can reduce memory and CPU usage to serve fetches,
+	but might result in sending a slightly larger pack. Defaults to
+	true.
 
 pack.island::
 	An extended regular expression configuring a set of delta

-Peff

  reply	other threads:[~2019-12-09  7:14 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-15 14:15 [PATCH v3 0/9] Rewrite packfile reuse code Christian Couder
2019-11-15 14:15 ` [PATCH v3 1/9] builtin/pack-objects: report reused packfile objects Christian Couder
2019-12-09  6:24   ` Jeff King
2019-12-11 13:48     ` Christian Couder
2019-11-15 14:15 ` [PATCH v3 2/9] packfile: expose get_delta_base() Christian Couder
2019-12-09  6:26   ` Jeff King
2019-11-15 14:15 ` [PATCH v3 3/9] ewah/bitmap: introduce bitmap_word_alloc() Christian Couder
2019-12-09  6:28   ` Jeff King
2019-12-11 13:50     ` Christian Couder
2019-12-12  5:45       ` Jeff King
2019-11-15 14:15 ` [PATCH v3 4/9] pack-bitmap: don't rely on bitmap_git->reuse_objects Christian Couder
2019-12-09  6:47   ` Jeff King
2019-12-13 13:26     ` Christian Couder
2019-11-15 14:15 ` [PATCH v3 5/9] pack-bitmap: introduce bitmap_walk_contains() Christian Couder
2019-12-09  7:06   ` Jeff King
2019-12-13 13:27     ` Christian Couder
2019-11-15 14:15 ` [PATCH v3 6/9] csum-file: introduce hashfile_total() Christian Couder
2019-12-09  7:07   ` Jeff King
2019-11-15 14:15 ` [PATCH v3 7/9] pack-objects: introduce pack.allowPackReuse Christian Couder
2019-12-09  7:14   ` Jeff King [this message]
2019-12-13 13:27     ` Christian Couder
2019-11-15 14:15 ` [PATCH v3 8/9] builtin/pack-objects: introduce obj_is_packed() Christian Couder
2019-12-09  7:14   ` Jeff King
2019-11-15 14:15 ` [PATCH v3 9/9] pack-objects: improve partial packfile reuse Christian Couder
2019-12-09  8:11   ` Jeff King
2019-12-18 11:26     ` Christian Couder
2019-12-19  0:42       ` Jeff King
2020-01-23 22:29         ` Christian Couder
2019-11-15 18:03 ` [PATCH v3 0/9] Rewrite packfile reuse code Jonathan Tan
2019-11-25  6:30   ` Junio C Hamano
2019-11-25  6:36     ` Junio C Hamano
2019-12-06 21:42       ` Junio C Hamano
2019-12-07 10:12         ` Christian Couder
2019-12-07 20:47           ` Johannes Schindelin
2019-12-08  7:53             ` Christian Couder
2019-12-08  8:54               ` Johannes Schindelin
2019-12-08 10:26                 ` Christian Couder
2019-12-08 10:45                   ` Johannes Schindelin
2019-12-09  6:18                 ` Jeff King
2019-12-09  9:28                   ` Johannes Schindelin
2019-12-09 19:00                   ` Junio C Hamano
2019-12-09 19:05                   ` Junio C Hamano

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