From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, sandals@crustytoothpaste.net,
Junio C Hamano <gitster@pobox.com>,
Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH v3 6/6] commit-graph: remove Future Work section
Date: Wed, 01 May 2019 16:58:45 +0200 [thread overview]
Message-ID: <87o94mql0a.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <e72bca6c784c5fc727ae4cf661526eec346c478c.1556716273.git.gitgitgadget@gmail.com>
On Wed, May 01 2019, Derrick Stolee via GitGitGadget wrote:
> The commit-graph feature began with a long list of planned
> benefits, most of which are now complete. The future work
> section has only a few items left.
>
> As for making more algorithms aware of generation numbers,
> some are only waiting for generation number v2 to ensure the
> performance matches the existing behavior using commit date.
>
> It is unlikely that we will ever send a commit-graph file
> as part of the protocol, since we would need to verify the
> data, and that is as expensive as writing a commit-graph from
> scratch. If we want to start trusting remote content, then
> that item can be investigated again.
My best of 3 times for "write" followed by "verify" on linux.git are
8.7/7.9 real/user for "write" and 5.2/4.9 real/user for "write".
So that's a reduction of ~40%. I have another big in-house repo where I
get similar numbers of 17/16 for "write" and 10/9 for "verify". Both for
a commit-graph file on the order of 50MB where it would be quicker for
me to download and verify it if the protocol supported it.
I'm not clamoring to make it part of the protocol, but the claim that
"verify" needs to do the equivalent of "write" seems to be demonstrably
wrong, or perhaps "verify" isn't doing all the work it should be doing?
> While there is more work to be done on the feature, having
> a section of the docs devoted to a TODO list is wasteful and
> hard to keep up-to-date.
Agreed, whatever we decide to do in the future I think it makes sense to
remove this section from the docs, although perhaps the commit message
should be amended per the above :)
> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
> ---
> Documentation/technical/commit-graph.txt | 17 -----------------
> 1 file changed, 17 deletions(-)
>
> diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
> index 7805b0968c..fb53341d5e 100644
> --- a/Documentation/technical/commit-graph.txt
> +++ b/Documentation/technical/commit-graph.txt
> @@ -127,23 +127,6 @@ Design Details
> helpful for these clones, anyway. The commit-graph will not be read or
> written when shallow commits are present.
>
> -Future Work
> ------------
> -
> -- After computing and storing generation numbers, we must make graph
> - walks aware of generation numbers to gain the performance benefits they
> - enable. This will mostly be accomplished by swapping a commit-date-ordered
> - priority queue with one ordered by generation number. The following
> - operations are important candidates:
> -
> - - 'log --topo-order'
> - - 'tag --merged'
> -
> -- A server could provide a commit-graph file as part of the network protocol
> - to avoid extra calculations by clients. This feature is only of benefit if
> - the user is willing to trust the file, because verifying the file is correct
> - is as hard as computing it from scratch.
> -
> Related Links
> -------------
> [0] https://bugs.chromium.org/p/git/issues/detail?id=8
next prev parent reply other threads:[~2019-05-01 14:58 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-23 21:59 [PATCH 0/6] Create commit-graph file format v2 Derrick Stolee via GitGitGadget
2019-01-23 21:59 ` [PATCH 1/6] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-01-23 21:59 ` [PATCH 2/6] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-01-23 21:59 ` [PATCH 3/6] commit-graph: create new version flags Derrick Stolee via GitGitGadget
2019-01-23 21:59 ` [PATCH 4/6] commit-graph: add --version=<n> option Derrick Stolee via GitGitGadget
2019-01-24 9:31 ` Ævar Arnfjörð Bjarmason
2019-01-23 21:59 ` [PATCH 5/6] commit-graph: implement file format version 2 Derrick Stolee via GitGitGadget
2019-01-23 23:56 ` Jonathan Tan
2019-01-24 9:40 ` Ævar Arnfjörð Bjarmason
2019-01-24 14:34 ` Derrick Stolee
2019-03-21 9:21 ` Ævar Arnfjörð Bjarmason
2019-01-23 21:59 ` [PATCH 6/6] commit-graph: test verifying a corrupt v2 header Derrick Stolee via GitGitGadget
2019-01-23 23:59 ` Jonathan Tan
2019-01-24 23:05 ` [PATCH 0/6] Create commit-graph file format v2 Junio C Hamano
2019-01-24 23:39 ` Junio C Hamano
2019-01-25 13:54 ` Derrick Stolee
2019-04-24 19:58 ` [PATCH v2 0/5] " Derrick Stolee via GitGitGadget
2019-04-24 19:58 ` [PATCH v2 1/5] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-04-24 19:58 ` [PATCH v2 2/5] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-04-25 5:21 ` Junio C Hamano
2019-04-24 19:58 ` [PATCH v2 3/5] commit-graph: create new version flags Derrick Stolee via GitGitGadget
2019-04-25 5:29 ` Junio C Hamano
2019-04-25 11:09 ` Derrick Stolee
2019-04-25 21:31 ` Ævar Arnfjörð Bjarmason
2019-04-26 2:20 ` Junio C Hamano
2019-04-24 19:58 ` [PATCH v2 4/5] commit-graph: add --version=<n> option Derrick Stolee via GitGitGadget
2019-04-24 19:58 ` [PATCH v2 5/5] commit-graph: implement file format version 2 Derrick Stolee via GitGitGadget
2019-04-25 22:09 ` [PATCH v2 0/5] Create commit-graph file format v2 Ævar Arnfjörð Bjarmason
2019-04-26 2:28 ` Junio C Hamano
2019-04-26 8:33 ` Ævar Arnfjörð Bjarmason
2019-04-26 12:06 ` Derrick Stolee
2019-04-26 13:55 ` Ævar Arnfjörð Bjarmason
2019-04-27 12:57 ` Ævar Arnfjörð Bjarmason
2019-05-01 13:11 ` [PATCH v3 0/6] " Derrick Stolee via GitGitGadget
2019-05-01 13:11 ` [PATCH v3 1/6] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-05-01 14:46 ` Ævar Arnfjörð Bjarmason
2019-05-01 13:11 ` [PATCH v3 2/6] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-05-01 13:11 ` [PATCH v3 3/6] commit-graph: create new version parameter Derrick Stolee via GitGitGadget
2019-05-01 13:11 ` [PATCH v3 4/6] commit-graph: add --version=<n> option Derrick Stolee via GitGitGadget
2019-05-01 13:11 ` [PATCH v3 5/6] commit-graph: implement file format version 2 Derrick Stolee via GitGitGadget
2019-05-01 19:12 ` Ævar Arnfjörð Bjarmason
2019-05-01 19:56 ` Derrick Stolee
2019-05-01 13:11 ` [PATCH v3 6/6] commit-graph: remove Future Work section Derrick Stolee via GitGitGadget
2019-05-01 14:58 ` Ævar Arnfjörð Bjarmason [this message]
2019-05-01 19:59 ` Derrick Stolee
2019-05-01 20:25 ` [PATCH v3 0/6] Create commit-graph file format v2 Ævar Arnfjörð Bjarmason
2019-05-02 13:26 ` Derrick Stolee
2019-05-02 18:02 ` Ævar Arnfjörð Bjarmason
2019-05-03 12:47 ` Derrick Stolee
2019-05-03 13:41 ` Ævar Arnfjörð Bjarmason
2019-05-06 8:27 ` Christian Couder
2019-05-06 13:47 ` Derrick Stolee
2019-05-03 14:16 ` SZEDER Gábor
2019-05-03 15:11 ` Derrick Stolee
2019-05-09 14:22 ` [PATCH v4 00/11] Commit-graph write refactor (was: Create commit-graph file format v2) Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 01/11] commit-graph: fix the_repository reference Derrick Stolee via GitGitGadget
2019-05-13 2:56 ` Junio C Hamano
2019-05-09 14:22 ` [PATCH v4 02/11] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-05-13 3:13 ` Junio C Hamano
2019-05-13 11:04 ` Derrick Stolee
2019-05-13 11:22 ` Derrick Stolee
2019-05-09 14:22 ` [PATCH v4 03/11] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-05-13 3:44 ` Junio C Hamano
2019-05-13 11:07 ` Derrick Stolee
2019-05-09 14:22 ` [PATCH v4 04/11] commit-graph: remove Future Work section Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 05/11] commit-graph: create write_commit_graph_context Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 06/11] commit-graph: extract fill_oids_from_packs() Derrick Stolee via GitGitGadget
2019-05-13 5:05 ` Junio C Hamano
2019-05-09 14:22 ` [PATCH v4 07/11] commit-graph: extract fill_oids_from_commit_hex() Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 08/11] commit-graph: extract fill_oids_from_all_packs() Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 09/11] commit-graph: extract count_distinct_commits() Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 10/11] commit-graph: extract copy_oids_to_commits() Derrick Stolee via GitGitGadget
2019-05-09 14:22 ` [PATCH v4 11/11] commit-graph: extract write_commit_graph_file() Derrick Stolee via GitGitGadget
2019-05-13 5:09 ` Junio C Hamano
2019-05-09 17:58 ` [PATCH v4 00/11] Commit-graph write refactor (was: Create commit-graph file format v2) Josh Steadmon
2019-06-12 13:29 ` [PATCH v5 " Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 01/11] commit-graph: fix the_repository reference Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 02/11] commit-graph: return with errors during write Derrick Stolee via GitGitGadget
2019-06-29 17:23 ` SZEDER Gábor
2019-07-01 12:19 ` Derrick Stolee
2019-06-12 13:29 ` [PATCH v5 03/11] commit-graph: collapse parameters into flags Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 04/11] commit-graph: remove Future Work section Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 05/11] commit-graph: create write_commit_graph_context Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 06/11] commit-graph: extract fill_oids_from_packs() Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 08/11] commit-graph: extract fill_oids_from_all_packs() Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 07/11] commit-graph: extract fill_oids_from_commit_hex() Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 09/11] commit-graph: extract count_distinct_commits() Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 10/11] commit-graph: extract copy_oids_to_commits() Derrick Stolee via GitGitGadget
2019-06-12 13:29 ` [PATCH v5 11/11] commit-graph: extract write_commit_graph_file() Derrick Stolee via GitGitGadget
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