From: ZheNing Hu <adlternative@gmail.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: ZheNing Hu via GitGitGadget <gitgitgadget@gmail.com>,
Git List <git@vger.kernel.org>,
Junio C Hamano <gitster@pobox.com>,
Christian Couder <christian.couder@gmail.com>,
Hariom Verma <hariom18599@gmail.com>,
Bagas Sanjaya <bagasdotme@gmail.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH 12/15] [GSOC] cat-file: reuse ref-filter logic
Date: Sat, 3 Jul 2021 19:45:30 +0800 [thread overview]
Message-ID: <CAOLTT8RdujpQ2uKEWPyG0HGkUz_EsONw3hEZ6YAhpmQc5rgohA@mail.gmail.com> (raw)
In-Reply-To: <877di8al8n.fsf@evledraar.gmail.com>
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Ævar Arnfjörð Bjarmason <avarab@gmail.com> 于2021年7月2日周五 下午9:39写道:
>
>
> On Thu, Jul 01 2021, ZheNing Hu via GitGitGadget wrote:
>
> > From: ZheNing Hu <adlternative@gmail.com>
> >
> > In order to let cat-file use ref-filter logic, let's do the
> > following:
> >
> > 1. Change the type of member `format` in struct `batch_options`
> > to `ref_format`, we will pass it to ref-filter later.
> > 2. Let `batch_objects()` add atoms to format, and use
> > `verify_ref_format()` to check atoms.
> > 3. Use `format_ref_array_item()` in `batch_object_write()` to
> > get the formatted data corresponding to the object. If the
> > return value of `format_ref_array_item()` is equals to zero,
> > use `batch_write()` to print object data; else if the return
> > value is less than zero, use `die()` to print the error message
> > and exit; else if return value is greater than zero, only print
> > the error message, but don't exit.
> > 4. Use free_ref_array_item_value() to free ref_array_item's
> > value.
> >
> > Most of the atoms in `for-each-ref --format` are now supported,
> > such as `%(tree)`, `%(parent)`, `%(author)`, `%(tagger)`, `%(if)`,
> > `%(then)`, `%(else)`, `%(end)`. But these atoms will be rejected:
> > `%(refname)`, `%(symref)`, `%(upstream)`, `%(push)`, `%(worktreepath)`,
> > `%(flag)`, `%(HEAD)`, because these atoms are unique to those objects
> > that pointed to by a ref, "for-each-ref"'s family can naturally use
> > these atoms, but not all objects are pointed to be a ref, so "cat-file"
> > will not be able to use them.
> >
> > The performance for `git cat-file --batch-all-objects
> > --batch-check` on the Git repository itself with performance
> > testing tool `hyperfine` changes from 669.4 ms ± 31.1 ms to
> > 1.134 s ± 0.063 s.
> >
> > The performance for `git cat-file --batch-all-objects --batch
> >>/dev/null` on the Git repository itself with performance testing
> > tool `time` change from "27.37s user 0.29s system 98% cpu 28.089
> > total" to "33.69s user 1.54s system 87% cpu 40.258 total".
>
> This new feature is really nice, but that's a really bad performance
> regression. A lot of software in the wild relies on "cat-file --batch"
> to be *the* performant interface to git for mass-extrction of object
> data.
>
Thanks, this performance is indeed worrying.
> That's in increase of ~70% and ~20%, respectively. Have you dug into
> (e.g. with a profiler) where we're now spending all this time?
See this two attachment about performance flame graph,
oid_object_info_extended() in get_object() is the key to performance
limitations.
--
ZheNing Hu
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next prev parent reply other threads:[~2021-07-03 11:45 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 16:07 [PATCH 00/15] [GSOC] cat-file: reuse ref-filter logic ZheNing Hu via GitGitGadget
2021-07-01 16:07 ` [PATCH 01/15] [GSOC] ref-filter: add obj-type check in grab contents ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 02/15] [GSOC] ref-filter: add %(raw) atom ZheNing Hu via GitGitGadget
2021-07-02 13:22 ` Ævar Arnfjörð Bjarmason
2021-07-03 5:14 ` ZheNing Hu
2021-07-01 16:08 ` [PATCH 03/15] [GSOC] ref-filter: --format=%(raw) re-support --perl ZheNing Hu via GitGitGadget
2021-07-02 13:29 ` Ævar Arnfjörð Bjarmason
2021-07-03 5:14 ` ZheNing Hu
2021-07-01 16:08 ` [PATCH 04/15] [GSOC] ref-filter: use non-const ref_format in *_atom_parser() ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 05/15] [GSOC] ref-filter: add %(rest) atom ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 06/15] [GSOC] ref-filter: pass get_object() return value to their callers ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 07/15] [GSOC] ref-filter: introduce free_ref_array_item_value() function ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 08/15] [GSOC] ref-filter: add cat_file_mode in struct ref_format ZheNing Hu via GitGitGadget
2021-07-02 13:32 ` Ævar Arnfjörð Bjarmason
2021-07-02 19:28 ` Eric Sunshine
2021-07-02 22:11 ` Christian Couder
2021-07-03 5:55 ` ZheNing Hu
2021-07-05 7:17 ` Ævar Arnfjörð Bjarmason
2021-07-01 16:08 ` [PATCH 09/15] [GSOC] ref-filter: modify the error message and value in get_object ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 10/15] [GSOC] cat-file: add has_object_file() check ZheNing Hu via GitGitGadget
2021-07-02 13:34 ` Ævar Arnfjörð Bjarmason
2021-07-03 5:50 ` ZheNing Hu
2021-07-01 16:08 ` [PATCH 11/15] [GSOC] cat-file: change batch_objects parameter name ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 12/15] [GSOC] cat-file: reuse ref-filter logic ZheNing Hu via GitGitGadget
2021-07-02 13:36 ` Ævar Arnfjörð Bjarmason
2021-07-02 13:45 ` Christian Couder
2021-07-03 11:45 ` ZheNing Hu [this message]
2021-07-03 13:37 ` Ævar Arnfjörð Bjarmason
2021-07-04 11:10 ` ZheNing Hu
2021-07-05 7:18 ` Ævar Arnfjörð Bjarmason
2021-07-03 14:17 ` ZheNing Hu
2021-07-01 16:08 ` [PATCH 13/15] [GSOC] cat-file: reuse err buf in batch_object_write() ZheNing Hu via GitGitGadget
2021-07-01 16:08 ` [PATCH 14/15] [GSOC] cat-file: re-implement --textconv, --filters options ZheNing Hu via GitGitGadget
2021-07-01 19:55 ` Junio C Hamano
2021-07-01 20:11 ` Junio C Hamano
2021-07-02 12:46 ` ZheNing Hu
2021-07-02 15:27 ` Junio C Hamano
2021-07-03 6:17 ` ZheNing Hu
2021-07-01 16:08 ` [PATCH 15/15] [GSOC] ref-filter: remove grab_oid() function ZheNing Hu via GitGitGadget
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