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From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: [PATCH 0/4] optimizing upload-pack ref peeling
Date: Thu, 4 Oct 2012 03:56:09 -0400	[thread overview]
Message-ID: <20121004075609.GA1355@sigill.intra.peff.net> (raw)
In-Reply-To: <CACBZZX5Sm++Wjyoue-qk7TjwxUM3QihXfWGtEHhOq=VtkgvNbQ@mail.gmail.com>

On Thu, Oct 04, 2012 at 01:54:47AM +0200, Ævar Arnfjörð Bjarmason wrote:

> > Hmm. It seems like we should not need to open the tags at all. The main
> > reason is to produce the "peeled" advertisement just after it. But for a
> > packed ref with a modern version of git that supports the "peeled"
> > extension, we should already have that information.
> 
> B.t.w. do you plan to submit this as a non-hack, I'd like to have it
> in git.git, so if you're not going to I could pick it up and clean it
> up a bit. But I think it would be better coming from you.

Here's a cleaned-up version. I realized that peel_ref actually is quite
close to what we want; the key thing is that when you are calling it
from a for_each_ref loop it will not only use peeled information from
packed-refs (if available), but it will also short-circuit the ref
lookup for non-packed refs. So it really does what we want.

I put some timings into the final patch. The results are very satisfying
from a pure numbers standpoint. However, I'm not 100% sure this is all
that useful a benchmark. The repos where you get a noticeable benefit
are quite big, so I suspect the time to send the advertisements out over
the wire will dominate. Still, a CPU second saved is a CPU second
earned.

And the series actually ends up making the code cleaner and shares some
of the optimizations I put into upload-pack with other users of
peel_ref. So I think I'd be inclined to use it, even if the speedup
doesn't help that much in practice. We'll see what others think.

  [1/4]: peel_ref: use faster deref_tag_noverify
  [2/4]: peel_ref: do not return a null sha1
  [3/4]: peel_ref: check object type before loading
  [4/4]: upload-pack: use peel_ref for ref advertisements

-Peff

  reply	other threads:[~2012-10-04 22:02 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-03 12:36 upload-pack is slow with lots of refs Ævar Arnfjörð Bjarmason
2012-10-03 13:06 ` Nguyen Thai Ngoc Duy
2012-10-03 18:03 ` Jeff King
2012-10-03 18:53   ` Junio C Hamano
2012-10-03 18:55     ` Jeff King
2012-10-03 19:41       ` Shawn Pearce
2012-10-03 20:13         ` Jeff King
2012-10-04 21:52           ` Sascha Cunz
2012-10-05  0:20             ` Jeff King
2012-10-05  6:24         ` Johannes Sixt
2012-10-05 16:57           ` Shawn Pearce
2012-10-08 15:05             ` Johannes Sixt
2012-10-09  6:46               ` Shawn Pearce
2012-10-09 20:30                 ` Johannes Sixt
2012-10-09 20:46                   ` Johannes Sixt
2012-10-03 20:16   ` Ævar Arnfjörð Bjarmason
2012-10-03 21:20     ` Jeff King
2012-10-03 22:15       ` Ævar Arnfjörð Bjarmason
2012-10-03 23:15         ` Jeff King
2012-10-03 23:54           ` Ævar Arnfjörð Bjarmason
2012-10-04  7:56             ` Jeff King [this message]
2012-10-04  7:58               ` [PATCH 1/4] peel_ref: use faster deref_tag_noverify Jeff King
2012-10-04 18:24                 ` Junio C Hamano
2012-10-04  8:00               ` [PATCH 2/4] peel_ref: do not return a null sha1 Jeff King
2012-10-04 18:32                 ` Junio C Hamano
2012-10-04  8:02               ` [PATCH 3/4] peel_ref: check object type before loading Jeff King
2012-10-04 19:06                 ` Junio C Hamano
2012-10-04 19:41                   ` Jeff King
2012-10-04 20:41                     ` Junio C Hamano
2012-10-04 21:59                       ` Jeff King
2012-10-04  8:03               ` [PATCH 4/4] upload-pack: use peel_ref for ref advertisements Jeff King
2012-10-04  8:04               ` [PATCH 0/4] optimizing upload-pack ref peeling Jeff King
2012-10-04  9:01                 ` Ævar Arnfjörð Bjarmason
2012-10-04 12:14                   ` Nazri Ramliy
2012-10-03 22:32   ` upload-pack is slow with lots of refs Ævar Arnfjörð Bjarmason
2012-10-03 23:21     ` Jeff King
2012-10-03 23:47       ` Ævar Arnfjörð Bjarmason
2012-10-03 19:13 ` Junio C Hamano

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