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From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
To: SZEDER Gábor <szeder.dev@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>,
	Derrick Stolee <stolee@gmail.com>, Jeff King <peff@peff.net>,
	Nguyễn Thái Ngọc Duy <pclouds@gmail.com>,
	Eric Sunshine <sunshine@sunshineco.com>,
	git@vger.kernel.org
Subject: Re: [PATCH] commit-graph: don't show progress percentages while expanding reachable commits
Date: Fri, 22 Mar 2019 18:23:03 +0100
Message-ID: <87ef6ydds8.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <20190322154943.GF22459@szeder.dev>


On Fri, Mar 22 2019, SZEDER Gábor wrote:

> On Fri, Mar 22, 2019 at 04:11:24PM +0100, Ævar Arnfjörð Bjarmason wrote:
>>
>> On Fri, Mar 22 2019, SZEDER Gábor wrote:
>>
>> > On Fri, Mar 22, 2019 at 03:28:34PM +0100, Ævar Arnfjörð Bjarmason wrote:
>> >>
>> >> On Fri, Mar 22 2019, SZEDER Gábor wrote:
>> >>
>> >> > On Fri, Mar 22, 2019 at 12:11:26PM +0100, Ævar Arnfjörð Bjarmason wrote:
>> >> >>
>> >> >> On Fri, Mar 22 2019, SZEDER Gábor wrote:
>> >> >>
>> >> >> > Commit 49bbc57a57 (commit-graph write: emit a percentage for all
>> >> >> > progress, 2019-01-19) was a bit overeager when it added progress
>> >> >> > percentages to the "Expanding reachable commits in commit graph" phase
>> >> >> > as well, because most of the time the number of commits that phase has
>> >> >> > to iterate over is not known in advance and grows significantly, and,
>> >> >> > consequently, we end up with nonsensical numbers:
>> >> >> >
>> >> >> >   $ git commit-graph write --reachable
>> >> >> >   Expanding reachable commits in commit graph: 138606% (824706/595), done.
>> >> >> >   [...]
>> >> >> >
>> >> >> >   $ git rev-parse v5.0 | git commit-graph write --stdin-commits
>> >> >> >   Expanding reachable commits in commit graph: 81264400% (812644/1), done.
>> >> >> >   [...]
>> >> >> >
>> >> >> > Therefore, don't show progress percentages in the "Expanding reachable
>> >> >> > commits in commit graph" phase.
>> >> >>
>> >> >> There's indeed a bug here as your examples show, but there *are* cases
>> >> >> where it's correct, as the commit message for my patch on "master" shows
>> >> >> there's cases where we correctly.
>> >> >>
>> >> >> So this "fixes" things by always removing the progress, why not instead
>> >> >> pass down the state to close_reachable() about what we're walking over,
>> >> >> so we can always show progress, or at least in some cases?
>> >> >
>> >> > The cases where it does display correct percentages are exceptional,
>> >> > and doesn't worth the effort to try to find out whether ther current
>> >> > operation happens to be such a case.
>> >>
>> >> It's the "write" entry point without arguments that displays the correct
>> >> progress. So not exceptional, but yeah, it's not what we use on "gc".
>> >
>> > Bit it displays the correct number only if all the reachable commits
>> > are in packfiles, which is not necessarily the case (e.g. unpacked
>> > small packs during 'git fetch').
>>
>> No, argument-less "write" only considers packed commits.
>
> No, it considers packed commits as starting points, and then expands
> to all reachable commits, that's what that loop in question is about.
>
>   $ git init
>   Initialized empty Git repository in /tmp/test/.git/
>   $ echo >file
>   $ git add file
>   $ git commit -q -m initial
>   $ echo 1 >file
>   $ git commit -q -m 1 file
>   $ git rev-parse HEAD | git pack-objects
>   .git/objects/pack/pack
>   Enumerating objects: 1, done.
>   Counting objects: 100% (1/1), done.
>   ece3ff72952af2b28e048fa5c58db88c44312876
>   Writing objects: 100% (1/1), done.
>   Total 1 (delta 0), reused 0 (delta 0)
>   $ git commit-graph write
>   Computing commit graph generation numbers: 100% (2/2), done.

Ah, indeed. I think in practice it'll be unlikely to happen in practice
except on servers due to receive.unpackLimit, and then it won't be off
by much.

So I think it's best to do something like my WIP patch upthread + the
"snap to 100%" at the end behavior. I'll try to clean that up / test it
/ submit that sometime soon.

>> >> In any case, the problem is that sometimes we've walked the full set of
>> >> commits already, and some other times we haven't.
>> >
>> > ... and that we can't really be sure whether we've walked the full set
>> > of commits until after this loop.
>>
>> I'm fairly sure we can when we start with a full walk. See my
>> explanation in <87imwbc6x8.fsf@evledraar.gmail.com>, but I may have
>> missed something.
>>
>> >> So in cases where we have we can show progress, and as a TODO (I think
>> >> this came up in previous discussions), we could do better if we had a
>> >> approximate_commit_count().
>> >>
>> >> In any case, the below fix seems correct to me, but I haven't poked it
>> >> much. It *does* suffer from a theoretical race with the progress bar
>> >> similar to d9b1b309cf ("commit-graph write: show progress for object
>> >> search", 2019-01-19), but I work around it in the same way:
>> >>
>> >> diff --git a/commit-graph.c b/commit-graph.c
>> >> index 47e9be0a3a..0fab3d8b2b 100644
>> >> --- a/commit-graph.c
>> >> +++ b/commit-graph.c
>> >> @@ -693,7 +693,8 @@ static void add_missing_parents(struct packed_oid_list *oids, struct commit *com
>> >>  	}
>> >>  }
>> >>
>> >> -static void close_reachable(struct packed_oid_list *oids, int report_progress)
>> >> +static void close_reachable(struct packed_oid_list *oids, int report_progress,
>> >> +			    uint64_t oids_count_for_progress)
>> >>  {
>> >>  	int i;
>> >>  	struct commit *commit;
>> >> @@ -717,7 +718,8 @@ static void close_reachable(struct packed_oid_list *oids, int report_progress)
>> >>  	 */
>> >>  	if (report_progress)
>> >>  		progress = start_delayed_progress(
>> >> -			_("Expanding reachable commits in commit graph"), oids->nr);
>> >> +			_("Expanding reachable commits in commit graph"),
>> >> +			oids_count_for_progress);
>> >>  	for (i = 0; i < oids->nr; i++) {
>> >>  		display_progress(progress, i + 1);
>> >>  		commit = lookup_commit(the_repository, &oids->list[i]);
>> >> @@ -725,6 +727,8 @@ static void close_reachable(struct packed_oid_list *oids, int report_progress)
>> >>  		if (commit && !parse_commit(commit))
>> >>  			add_missing_parents(oids, commit);
>> >>  	}
>> >> +	if (oids->nr < oids_count_for_progress)
>> >> +		display_progress(progress, oids_count_for_progress);
>> >>  	stop_progress(&progress);
>> >>
>> >>  	if (report_progress)
>> >> @@ -829,6 +833,7 @@ void write_commit_graph(const char *obj_dir,
>> >>  	uint64_t progress_cnt = 0;
>> >>  	struct strbuf progress_title = STRBUF_INIT;
>> >>  	unsigned long approx_nr_objects;
>> >> +	uint64_t oids_count_for_progress = 0;
>> >>
>> >>  	if (!commit_graph_compatible(the_repository))
>> >>  		return;
>> >> @@ -934,9 +939,10 @@ void write_commit_graph(const char *obj_dir,
>> >>  		if (oids.progress_done < approx_nr_objects)
>> >>  			display_progress(oids.progress, approx_nr_objects);
>> >>  		stop_progress(&oids.progress);
>> >> +		oids_count_for_progress = oids.nr;
>> >>  	}
>> >>
>> >> -	close_reachable(&oids, report_progress);
>> >> +	close_reachable(&oids, report_progress, oids_count_for_progress);
>> >>
>> >>  	if (report_progress)
>> >>  		progress = start_delayed_progress(
>> >>

  parent reply index

Thread overview: 133+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-04 20:27 [PATCH 0/2] commit-graph: add progress output Ævar Arnfjörð Bjarmason
2018-09-04 20:27 ` [PATCH 1/2] commit-graph write: " Ævar Arnfjörð Bjarmason
2018-09-04 21:16   ` Eric Sunshine
2018-09-04 22:07   ` Junio C Hamano
2018-09-05 11:58     ` Derrick Stolee
2018-09-05 12:07       ` Ævar Arnfjörð Bjarmason
2018-09-05 21:46       ` Junio C Hamano
2018-09-05 22:12         ` Derrick Stolee
2018-09-07 15:11       ` Ævar Arnfjörð Bjarmason
2018-09-07 15:23         ` Ævar Arnfjörð Bjarmason
2018-09-07 17:15           ` Jeff King
2018-09-07 17:25             ` Derrick Stolee
2018-09-05 12:06   ` Derrick Stolee
2018-09-07 12:40   ` Ævar Arnfjörð Bjarmason
2018-09-07 13:12     ` Derrick Stolee
2018-09-04 20:27 ` [PATCH 2/2] commit-graph verify: " Ævar Arnfjörð Bjarmason
2018-09-04 22:10   ` Junio C Hamano
2018-09-05 12:07 ` [PATCH 0/2] commit-graph: " Derrick Stolee
2018-09-07 18:29 ` [PATCH v2 " Ævar Arnfjörð Bjarmason
2018-09-11 20:26   ` Junio C Hamano
2018-09-07 18:29 ` [PATCH v2 1/2] commit-graph write: " Ævar Arnfjörð Bjarmason
2018-09-21 20:01   ` Derrick Stolee
2018-09-21 21:43     ` Junio C Hamano
2018-09-21 21:57       ` Junio C Hamano
2018-09-07 18:29 ` [PATCH v2 2/2] commit-graph verify: " Ævar Arnfjörð Bjarmason
2018-09-16  6:55   ` Duy Nguyen
2018-09-17 15:33     ` [PATCH v3 0/2] commit-graph: " Ævar Arnfjörð Bjarmason
2018-09-17 15:33     ` [PATCH v3 1/2] commit-graph write: " Ævar Arnfjörð Bjarmason
2018-10-10 20:37       ` SZEDER Gábor
2018-10-10 21:56         ` Ævar Arnfjörð Bjarmason
2018-10-10 22:19           ` SZEDER Gábor
2018-10-10 22:37             ` Ævar Arnfjörð Bjarmason
2018-10-11 17:52               ` Ævar Arnfjörð Bjarmason
2018-10-15 16:05                 ` SZEDER Gábor
2018-10-12  6:09         ` Junio C Hamano
2018-10-12 15:07           ` Ævar Arnfjörð Bjarmason
2018-10-12 15:12             ` Derrick Stolee
2018-10-15 16:54       ` SZEDER Gábor
2018-11-19 16:02         ` SZEDER Gábor
2018-11-19 20:23           ` [PATCH] commit-graph: split up close_reachable() " Ævar Arnfjörð Bjarmason
2018-11-19 20:38             ` Derrick Stolee
2018-11-19 22:57             ` SZEDER Gábor
2018-11-20 15:04               ` [PATCH 0/6] commit-graph write: progress output improvements Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 1/6] commit-graph write: rephrase confusing progress output Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 2/6] commit-graph write: add more " Ævar Arnfjörð Bjarmason
2018-11-20 16:58                 ` SZEDER Gábor
2018-11-20 19:50                   ` [PATCH v2 0/6] commit-graph write: progress output improvements Ævar Arnfjörð Bjarmason
2018-11-20 19:50                   ` [PATCH v2 1/6] commit-graph write: rephrase confusing progress output Ævar Arnfjörð Bjarmason
2018-11-20 19:50                   ` [PATCH v2 2/6] commit-graph write: add more " Ævar Arnfjörð Bjarmason
2018-11-20 23:38                     ` SZEDER Gábor
2018-11-20 19:50                   ` [PATCH v2 3/6] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2018-11-20 19:50                   ` [PATCH v2 4/6] commit-graph write: add more describing progress output Ævar Arnfjörð Bjarmason
2018-11-20 19:50                   ` [PATCH v2 5/6] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2018-11-20 19:50                   ` [PATCH v2 6/6] commit-graph write: add even more progress output Ævar Arnfjörð Bjarmason
2018-11-21  1:23                   ` SZEDER Gábor
2018-11-21  1:25                     ` [PATCH 1/2] commit-graph: rename 'num_extra_edges' variable to 'num_large_edges' SZEDER Gábor
2018-11-21  3:29                       ` Junio C Hamano
2018-11-21 11:32                         ` Derrick Stolee
2019-01-18 17:05                           ` [PATCH v2 0/2] commit-graph: minor cleanup and optimization SZEDER Gábor
2019-01-18 17:05                             ` [PATCH v2 1/2] commit-graph: rename "large edges" to "extra edges" SZEDER Gábor
2019-01-18 17:05                             ` [PATCH v2 2/2] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily SZEDER Gábor
2019-01-19  9:32                               ` Martin Ågren
2019-01-18 19:41                             ` [PATCH v2 0/2] commit-graph: minor cleanup and optimization Junio C Hamano
2018-11-21  1:26                     ` [PATCH 2/2] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily SZEDER Gábor
2018-11-21 11:33                       ` Derrick Stolee
2018-11-22 13:28                       ` [PATCH v3 00/10] commit-graph write: progress output improvements Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 01/10] commit-graph: rename 'num_extra_edges' variable to 'num_large_edges' Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 0/9] commit-graph write: progress output improvements Ævar Arnfjörð Bjarmason
2019-01-19  1:26                             ` Junio C Hamano
2019-01-19 20:21                             ` [PATCH v6 00/10] " Ævar Arnfjörð Bjarmason
2019-01-22 18:30                               ` Derrick Stolee
2019-01-23 17:52                                 ` Junio C Hamano
2019-01-22 19:37                               ` Junio C Hamano
2019-01-19 20:21                             ` [PATCH v6 01/10] commit-graph write: use pack order when finding commits Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 02/10] commit-graph: rename "large edges" to "extra edges" Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 03/10] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily Ævar Arnfjörð Bjarmason
2019-01-23 17:51                               ` [PATCH v6.1 03/10] commit-graph: don't call write_graph_chunk_extra_edges() unnecessarily SZEDER Gábor
2019-01-19 20:21                             ` [PATCH v6 04/10] commit-graph write: add "Writing out" progress output Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 05/10] commit-graph write: more descriptive "writing out" output Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 06/10] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 07/10] commit-graph write: add more descriptive progress output Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 08/10] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 09/10] commit-graph write: add itermediate progress Ævar Arnfjörð Bjarmason
2019-01-19 20:21                             ` [PATCH v6 10/10] commit-graph write: emit a percentage for all progress Ævar Arnfjörð Bjarmason
2019-03-22 10:28                               ` [PATCH] commit-graph: don't show progress percentages while expanding reachable commits SZEDER Gábor
2019-03-22 11:11                                 ` Ævar Arnfjörð Bjarmason
2019-03-22 11:18                                   ` SZEDER Gábor
2019-03-22 14:28                                     ` Ævar Arnfjörð Bjarmason
2019-03-22 14:36                                       ` Ævar Arnfjörð Bjarmason
2019-03-22 14:55                                       ` SZEDER Gábor
2019-03-22 15:11                                         ` Ævar Arnfjörð Bjarmason
2019-03-22 15:49                                           ` SZEDER Gábor
2019-03-22 16:52                                             ` SZEDER Gábor
2019-03-22 17:23                                             ` Ævar Arnfjörð Bjarmason [this message]
2019-01-16 13:29                           ` [PATCH v5 1/9] commit-graph: rename 'num_extra_edges' variable to 'num_large_edges' Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 2/9] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 3/9] commit-graph write: add "Writing out" progress output Ævar Arnfjörð Bjarmason
2019-01-18 17:16                             ` SZEDER Gábor
2019-01-16 13:29                           ` [PATCH v5 4/9] commit-graph write: more descriptive "writing out" output Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 5/9] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 6/9] commit-graph write: add more descriptive progress output Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 7/9] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 8/9] commit-graph write: add itermediate progress Ævar Arnfjörð Bjarmason
2019-01-16 13:29                           ` [PATCH v5 9/9] commit-graph write: emit a percentage for all progress Ævar Arnfjörð Bjarmason
2019-01-17 13:23                             ` [PATCH] commit-graph write: use pack order when finding commits Ævar Arnfjörð Bjarmason
2019-01-17 15:09                               ` Derrick Stolee
2019-01-17 16:35                                 ` Derrick Stolee
2018-11-22 15:39                         ` [PATCH v4 02/10] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 03/10] commit-graph write: rephrase confusing progress output Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 04/10] commit-graph write: add "Writing out" " Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 05/10] commit-graph write: more descriptive "writing out" output Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 06/10] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 07/10] commit-graph write: add more descriptive progress output Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 08/10] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 09/10] commit-graph write: add itermediate progress Ævar Arnfjörð Bjarmason
2018-11-22 15:39                         ` [PATCH v4 10/10] commit-graph write: emit a percentage for all progress Ævar Arnfjörð Bjarmason
2018-11-22 18:59                         ` [PATCH v3 00/10] commit-graph write: progress output improvements Eric Sunshine
2018-11-22 13:28                       ` [PATCH v3 01/10] commit-graph: rename 'num_extra_edges' variable to 'num_large_edges' Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 02/10] commit-graph: don't call write_graph_chunk_large_edges() unnecessarily Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 03/10] commit-graph write: rephrase confusing progress output Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 04/10] commit-graph write: add "Writing out" " Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 05/10] commit-graph write: more descriptive "writing out" output Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 06/10] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 07/10] commit-graph write: add more descriptive progress output Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 08/10] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 09/10] commit-graph write: add itermediate progress Ævar Arnfjörð Bjarmason
2018-11-22 13:28                       ` [PATCH v3 10/10] commit-graph write: emit a percentage for all progress Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 3/6] commit-graph write: show progress for object search Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 4/6] commit-graph write: add more describing progress output Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 5/6] commit-graph write: remove empty line for readability Ævar Arnfjörð Bjarmason
2018-11-20 15:04               ` [PATCH 6/6] commit-graph write: add even more progress output Ævar Arnfjörð Bjarmason
2018-09-17 15:33     ` [PATCH v3 2/2] commit-graph verify: add " Ævar Arnfjörð Bjarmason

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