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From: Taylor Blau <me@ttaylorr.com>
To: Derrick Stolee <stolee@gmail.com>
Cc: Taylor Blau <me@ttaylorr.com>,
	git@vger.kernel.org, peff@peff.net, dstolee@microsoft.com
Subject: Re: [PATCH 06/10] commit-graph.c: sort index into commits list
Date: Tue, 4 Aug 2020 16:10:06 -0400	[thread overview]
Message-ID: <20200804201006.GC89277@syl.lan> (raw)
In-Reply-To: <8bf3b41e-a597-3691-66e0-2be2f5f7e15e@gmail.com>

On Tue, Aug 04, 2020 at 08:31:53AM -0400, Derrick Stolee wrote:
> On 8/3/2020 2:57 PM, Taylor Blau wrote:
> > For locality, 'compute_bloom_filters()' sorts the commits for which it
> > wants to compute Bloom filters in a preferred order (cf., 3d11275505
> > (commit-graph: examine commits by generation number, 2020-03-30) for
> > details).
> >
> > The subsequent patch will want to recover the new graph position of each
> > commit. Since the 'packed_commit_list' already stores a double-pointer,
> > avoid a 'COPY_ARRAY' and instead keep track of an index into the
> > original list. (Use an integer index instead of a memory address, since
> > this involves a needlessly confusing triple-pointer).
>
> It took me a little while to grok that we are switching from sorting
> a list of commit pointers to sorting a list of integers. However, that
> makes a lot of sense. It preserves the commit list sorted by OID for
> binary search, which you will need soon. Perhaps another change would
> need that at another time, too.

Yeah. I had to spend some additional time with this patch (at least back
when it was written in terms of 'struct commit ***'s) to convince myself
of its correctness, too.

I think that this is ultimately the right thing, and that it is probably
as simple as I can make it without refactoring the packed_commit_list,
which I think is squarely outside the scope of this (already-large)
series ;).

> > Alter the two sorting routines 'commit_pos_cmp' and 'commit_gen_cmp' to
> > take into account the packed_commit_list they are sorting with respect
> > to. Since 'compute_bloom_filters()' is the only caller for each of those
> > comparison functions, no other call-sites need updating.
>
> Parsing the changes to these functions is the most complicated, because
> of the int-to-commit indirection. I think they are correct and as easy
> to read as possible.
>
> -Stolee

Thanks,
Taylor

  reply	other threads:[~2020-08-04 20:10 UTC|newest]

Thread overview: 117+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-03 18:57 [PATCH 00/10] more miscellaneous Bloom filter improvements Taylor Blau
2020-08-03 18:57 ` [PATCH 01/10] commit-graph: introduce 'get_bloom_filter_settings()' Taylor Blau
2020-08-04  7:24   ` Jeff King
2020-08-04 20:08     ` Taylor Blau
2020-08-03 18:57 ` [PATCH 02/10] commit-graph: pass a 'struct repository *' in more places Taylor Blau
2020-08-03 18:57 ` [PATCH 03/10] t4216: use an '&&'-chain Taylor Blau
2020-08-03 18:57 ` [PATCH 04/10] t/helper/test-read-graph.c: prepare repo settings Taylor Blau
2020-08-03 18:57 ` [PATCH 05/10] commit-graph: respect 'commitgraph.readChangedPaths' Taylor Blau
2020-08-03 18:57 ` [PATCH 06/10] commit-graph.c: sort index into commits list Taylor Blau
2020-08-04 12:31   ` Derrick Stolee
2020-08-04 20:10     ` Taylor Blau [this message]
2020-08-03 18:57 ` [PATCH 07/10] commit-graph: add large-filters bitmap chunk Taylor Blau
2020-08-03 18:59   ` Taylor Blau
2020-08-04 12:57   ` Derrick Stolee
2020-08-03 18:57 ` [PATCH 08/10] bloom: split 'get_bloom_filter()' in two Taylor Blau
2020-08-04 13:00   ` Derrick Stolee
2020-08-04 20:12     ` Taylor Blau
2020-08-03 18:57 ` [PATCH 09/10] commit-graph: rename 'split_commit_graph_opts' Taylor Blau
2020-08-03 18:57 ` [PATCH 10/10] builtin/commit-graph.c: introduce '--max-new-filters=<n>' Taylor Blau
2020-08-04 13:03   ` Derrick Stolee
2020-08-04 20:14     ` Taylor Blau
2020-08-05 17:01 ` [PATCH v2 00/14] more miscellaneous Bloom filter improvements Taylor Blau
2020-08-05 17:01   ` [PATCH v2 01/14] commit-graph: introduce 'get_bloom_filter_settings()' Taylor Blau
2020-08-05 17:02   ` [PATCH v2 02/14] t4216: use an '&&'-chain Taylor Blau
2020-08-05 17:02   ` [PATCH v2 03/14] commit-graph: pass a 'struct repository *' in more places Taylor Blau
2020-08-05 17:02   ` [PATCH v2 04/14] t/helper/test-read-graph.c: prepare repo settings Taylor Blau
2020-08-05 17:02   ` [PATCH v2 05/14] commit-graph: respect 'commitGraph.readChangedPaths' Taylor Blau
2020-08-05 17:02   ` [PATCH v2 06/14] commit-graph.c: store maximum changed paths Taylor Blau
2020-08-05 17:02   ` [PATCH v2 07/14] bloom: split 'get_bloom_filter()' in two Taylor Blau
2020-08-05 17:02   ` [PATCH v2 08/14] bloom: use provided 'struct bloom_filter_settings' Taylor Blau
2020-08-05 17:02   ` [PATCH v2 09/14] bloom/diff: properly short-circuit on max_changes Taylor Blau
2020-08-05 17:02   ` [PATCH v2 10/14] commit-graph.c: sort index into commits list Taylor Blau
2020-08-05 17:02   ` [PATCH v2 11/14] csum-file.h: introduce 'hashwrite_be64()' Taylor Blau
2020-08-05 17:02   ` [PATCH v2 12/14] commit-graph: add large-filters bitmap chunk Taylor Blau
2020-08-05 21:01     ` Junio C Hamano
2020-08-05 21:17       ` Taylor Blau
2020-08-05 22:21         ` Junio C Hamano
2020-08-05 22:25           ` Taylor Blau
2020-08-11 13:48             ` Taylor Blau
2020-08-11 18:59               ` Junio C Hamano
2020-08-05 17:03   ` [PATCH v2 13/14] commit-graph: rename 'split_commit_graph_opts' Taylor Blau
2020-08-05 17:03   ` [PATCH v2 14/14] builtin/commit-graph.c: introduce '--max-new-filters=<n>' Taylor Blau
2020-08-11 20:51 ` [PATCH v3 00/14] more miscellaneous Bloom filter improvements Taylor Blau
2020-08-11 20:51   ` [PATCH v3 01/14] commit-graph: introduce 'get_bloom_filter_settings()' Taylor Blau
2020-08-11 21:18     ` SZEDER Gábor
2020-08-11 21:21       ` Taylor Blau
2020-08-11 21:27         ` SZEDER Gábor
2020-08-11 21:34           ` Taylor Blau
2020-08-11 23:55             ` SZEDER Gábor
2020-08-12 11:48               ` Derrick Stolee
2020-08-14 20:17                 ` Taylor Blau
2020-08-11 20:51   ` [PATCH v3 02/14] t4216: use an '&&'-chain Taylor Blau
2020-08-11 20:51   ` [PATCH v3 03/14] commit-graph: pass a 'struct repository *' in more places Taylor Blau
2020-08-11 20:51   ` [PATCH v3 04/14] t/helper/test-read-graph.c: prepare repo settings Taylor Blau
2020-08-11 20:51   ` [PATCH v3 05/14] commit-graph: respect 'commitGraph.readChangedPaths' Taylor Blau
2020-08-11 20:51   ` [PATCH v3 06/14] commit-graph.c: store maximum changed paths Taylor Blau
2020-08-11 20:51   ` [PATCH v3 07/14] bloom: split 'get_bloom_filter()' in two Taylor Blau
2020-08-11 20:51   ` [PATCH v3 11/14] csum-file.h: introduce 'hashwrite_be64()' Taylor Blau
2020-08-11 20:51   ` [PATCH v3 08/14] bloom: use provided 'struct bloom_filter_settings' Taylor Blau
2020-08-11 20:51   ` [PATCH v3 09/14] bloom/diff: properly short-circuit on max_changes Taylor Blau
2020-08-11 20:52   ` [PATCH v3 10/14] commit-graph.c: sort index into commits list Taylor Blau
2020-08-11 20:52   ` [PATCH v3 12/14] commit-graph: add large-filters bitmap chunk Taylor Blau
2020-08-11 21:11     ` Derrick Stolee
2020-08-11 21:18       ` Taylor Blau
2020-08-11 22:05         ` Taylor Blau
2020-08-19 13:35     ` SZEDER Gábor
2020-09-02 20:23       ` Taylor Blau
2020-09-01 14:35     ` SZEDER Gábor
2020-09-02 20:40       ` Taylor Blau
2020-08-11 20:52   ` [PATCH v3 13/14] commit-graph: rename 'split_commit_graph_opts' Taylor Blau
2020-08-19  9:56     ` SZEDER Gábor
2020-09-02 21:02       ` Taylor Blau
2020-08-11 20:52   ` [PATCH v3 14/14] builtin/commit-graph.c: introduce '--max-new-filters=<n>' Taylor Blau
2020-08-12 11:49     ` SZEDER Gábor
2020-08-14 20:20       ` Taylor Blau
2020-08-17 22:50         ` SZEDER Gábor
2020-09-02 21:03           ` Taylor Blau
2020-08-12 12:29     ` Derrick Stolee
2020-08-14 20:10       ` Taylor Blau
2020-08-18 22:23     ` SZEDER Gábor
2020-09-03 16:35       ` Taylor Blau
2020-08-19  8:20     ` SZEDER Gábor
2020-09-03 16:42       ` Taylor Blau
2020-09-04  8:50         ` SZEDER Gábor
2020-09-01 14:36     ` SZEDER Gábor
2020-09-03 18:49       ` Taylor Blau
2020-09-03 21:45   ` [PATCH v3 00/14] more miscellaneous Bloom filter improvements Junio C Hamano
2020-09-03 22:33     ` Taylor Blau
2020-09-03 22:45 ` [PATCH v4 " Taylor Blau
2020-09-03 22:46   ` [PATCH v4 01/14] commit-graph: introduce 'get_bloom_filter_settings()' Taylor Blau
2020-09-03 22:46   ` [PATCH v4 02/14] t4216: use an '&&'-chain Taylor Blau
2020-09-03 22:46   ` [PATCH v4 03/14] commit-graph: pass a 'struct repository *' in more places Taylor Blau
2020-09-03 22:46   ` [PATCH v4 04/14] t/helper/test-read-graph.c: prepare repo settings Taylor Blau
2020-09-03 22:46   ` [PATCH v4 05/14] commit-graph: respect 'commitGraph.readChangedPaths' Taylor Blau
2020-09-03 22:46   ` [PATCH v4 06/14] commit-graph.c: store maximum changed paths Taylor Blau
2020-09-03 22:46   ` [PATCH v4 07/14] bloom: split 'get_bloom_filter()' in two Taylor Blau
2020-09-05 17:22     ` Jakub Narębski
2020-09-05 17:38       ` Taylor Blau
2020-09-05 17:50         ` Jakub Narębski
2020-09-05 18:01           ` Taylor Blau
2020-09-05 18:18             ` Jakub Narębski
2020-09-05 18:38               ` Taylor Blau
2020-09-05 18:55                 ` Taylor Blau
2020-09-05 19:04                   ` SZEDER Gábor
2020-09-05 19:49                     ` Taylor Blau
2020-09-06 21:52                       ` Junio C Hamano
2020-09-03 22:46   ` [PATCH v4 08/14] bloom: use provided 'struct bloom_filter_settings' Taylor Blau
2020-09-03 22:46   ` [PATCH v4 09/14] bloom/diff: properly short-circuit on max_changes Taylor Blau
2020-09-03 22:46   ` [PATCH v4 10/14] commit-graph.c: sort index into commits list Taylor Blau
2020-09-03 22:46   ` [PATCH v4 11/14] csum-file.h: introduce 'hashwrite_be64()' Taylor Blau
2020-09-04 20:18     ` René Scharfe
2020-09-04 20:22       ` Taylor Blau
2020-09-03 22:46   ` [PATCH v4 12/14] commit-graph: add large-filters bitmap chunk Taylor Blau
2020-09-03 22:46   ` [PATCH v4 13/14] commit-graph: rename 'split_commit_graph_opts' Taylor Blau
2020-09-04 15:20     ` Taylor Blau
2020-09-03 22:47   ` [PATCH v4 14/14] builtin/commit-graph.c: introduce '--max-new-filters=<n>' Taylor Blau
2020-09-04 14:39   ` [PATCH v4 00/14] more miscellaneous Bloom filter improvements Derrick Stolee

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