From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: git@vger.kernel.org
Cc: "Jeff King" <peff@peff.net>, "Junio C Hamano" <gitster@pobox.com>,
"Derrick Stolee" <stolee@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Stefan Beller" <sbeller@google.com>,
"Duy Nguyen" <pclouds@gmail.com>,
"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: [PATCH 0/4] Bloom filter experiment
Date: Tue, 9 Oct 2018 21:34:41 +0200 [thread overview]
Message-ID: <20181009193445.21908-1-szeder.dev@gmail.com> (raw)
In-Reply-To: <a66afe22-0523-c785-91e6-bf545683c67d@gmail.com>
To keep the ball rolling, here is my proof of concept in a somewhat
cleaned-up form, with still plenty of rough edges.
You can play around with it like this:
$ GIT_USE_POC_BLOOM_FILTER=$((8*1024*1024*8)) git commit-graph write
Computing commit graph generation numbers: 100% (52801/52801), done.
Computing bloom filter: 100% (52801/52801), done.
# Yeah, I even added progress indicator! :)
$ GIT_TRACE_BLOOM_FILTER=2 GIT_USE_POC_BLOOM_FILTER=y git rev-list --count --full-history HEAD -- t/valgrind/valgrind.sh
886
20:40:24.783699 revision.c:486 bloom filter total queries: 66095 definitely not: 64953 maybe: 1142 false positives: 256 fp ratio: 0.003873
The value of $GIT_USE_POC_BLOOM_FILTER only really matters when writing
the Bloom filter, and it specifies the number of bits in the filter's
bitmap, IOW the above command creates a 8MB Bloom filter. To make use
of the filter the variable can be anything non-empty.
Writing the Bloom filter is very slow as it is (yeah, that's why
bothered with the progress indicator ;). I wrote about it in patch 2's
commit message: the cause for about half of the slowness is rather
obvious, but I don't (yet) know what's responsible for the other half.
Not a single test... but I've run loops over all files in git.git
comparing 'git rev-list HEAD -- $file's output with and without the
Bloom filter, and, surprisingly, they match. My quick'n'dirty
experiments usually don't fare this well...
It's also available at:
https://github.com/szeder/git bloom-filter-experiment
SZEDER Gábor (4):
Add a (very) barebones Bloom filter implementation
commit-graph: write a Bloom filter containing changed paths for each
commit
revision.c: use the Bloom filter to speed up path-limited revision
walks
revision.c: add GIT_TRACE_BLOOM_FILTER for a bit of statistics
Makefile | 1 +
bloom-filter.c | 103 +++++++++++++++++++++++++++++++++++++++
bloom-filter.h | 39 +++++++++++++++
commit-graph.c | 116 ++++++++++++++++++++++++++++++++++++++++++++
pathspec.h | 1 +
revision.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 389 insertions(+)
create mode 100644 bloom-filter.c
create mode 100644 bloom-filter.h
--
2.19.1.409.g0a0ee5eb6b
next prev parent reply other threads:[~2018-10-09 19:35 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 13:23 We should add a "git gc --auto" after "git clone" due to commit graph Ævar Arnfjörð Bjarmason
2018-10-03 13:36 ` SZEDER Gábor
2018-10-03 13:42 ` Derrick Stolee
2018-10-03 14:18 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:01 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:17 ` SZEDER Gábor
2018-10-03 14:22 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:53 ` SZEDER Gábor
2018-10-03 15:19 ` Ævar Arnfjörð Bjarmason
2018-10-03 16:59 ` SZEDER Gábor
2018-10-05 6:09 ` Junio C Hamano
2018-10-10 22:07 ` SZEDER Gábor
2018-10-10 23:01 ` Ævar Arnfjörð Bjarmason
2018-10-03 19:08 ` Stefan Beller
2018-10-03 19:21 ` Jeff King
2018-10-03 20:35 ` Ævar Arnfjörð Bjarmason
2018-10-03 17:47 ` Stefan Beller
2018-10-03 18:47 ` Ævar Arnfjörð Bjarmason
2018-10-03 18:51 ` Jeff King
2018-10-03 18:59 ` Derrick Stolee
2018-10-03 19:18 ` Jeff King
2018-10-08 16:41 ` SZEDER Gábor
2018-10-08 16:57 ` Derrick Stolee
2018-10-08 18:10 ` SZEDER Gábor
2018-10-08 18:29 ` Derrick Stolee
2018-10-09 3:08 ` Jeff King
2018-10-09 13:48 ` Bloom Filters (was Re: We should add a "git gc --auto" after "git clone" due to commit graph) Derrick Stolee
2018-10-09 18:45 ` Ævar Arnfjörð Bjarmason
2018-10-09 18:46 ` Jeff King
2018-10-09 19:03 ` Derrick Stolee
2018-10-09 21:14 ` Jeff King
2018-10-09 23:12 ` Bloom Filters Jeff King
2018-10-09 23:13 ` [PoC -- do not apply 1/3] initial tree-bitmap proof of concept Jeff King
2018-10-09 23:14 ` [PoC -- do not apply 2/3] test-tree-bitmap: add "dump" mode Jeff King
2018-10-10 0:48 ` Junio C Hamano
2018-10-11 3:13 ` Jeff King
2018-10-09 23:14 ` [PoC -- do not apply 3/3] test-tree-bitmap: replace ewah with custom rle encoding Jeff King
2018-10-10 0:58 ` Junio C Hamano
2018-10-11 3:20 ` Jeff King
2018-10-11 12:33 ` Bloom Filters Derrick Stolee
2018-10-11 13:43 ` Jeff King
2018-10-09 21:30 ` We should add a "git gc --auto" after "git clone" due to commit graph SZEDER Gábor
2018-10-09 19:34 ` SZEDER Gábor [this message]
2018-10-09 19:34 ` [PATCH 1/4] Add a (very) barebones Bloom filter implementation SZEDER Gábor
2018-10-09 19:34 ` [PATCH 2/4] commit-graph: write a Bloom filter containing changed paths for each commit SZEDER Gábor
2018-10-09 21:06 ` Jeff King
2018-10-09 21:37 ` SZEDER Gábor
2018-10-09 19:34 ` [PATCH 3/4] revision.c: use the Bloom filter to speed up path-limited revision walks SZEDER Gábor
2018-10-09 19:34 ` [PATCH 4/4] revision.c: add GIT_TRACE_BLOOM_FILTER for a bit of statistics SZEDER Gábor
2018-10-09 19:47 ` [PATCH 0/4] Bloom filter experiment Derrick Stolee
2018-10-11 1:21 ` [PATCH 0/2] Per-commit filter proof of concept Jonathan Tan
2018-10-11 1:21 ` [PATCH 1/2] One filter per commit Jonathan Tan
2018-10-11 12:49 ` Derrick Stolee
2018-10-11 19:11 ` [PATCH] Per-commit and per-parent filters for 2 parents Jonathan Tan
2018-10-11 1:21 ` [PATCH 2/2] Only make bloom filter for first parent Jonathan Tan
2018-10-11 7:37 ` [PATCH 0/2] Per-commit filter proof of concept Ævar Arnfjörð Bjarmason
2018-10-15 14:39 ` [PATCH 0/4] Bloom filter experiment Derrick Stolee
2018-10-16 4:45 ` Junio C Hamano
2018-10-16 11:13 ` Derrick Stolee
2018-10-16 12:57 ` Ævar Arnfjörð Bjarmason
2018-10-16 13:03 ` Derrick Stolee
2018-10-18 2:00 ` Junio C Hamano
2018-10-16 23:41 ` Jonathan Tan
2018-10-08 23:02 ` We should add a "git gc --auto" after "git clone" due to commit graph Junio C Hamano
2018-10-03 14:32 ` Duy Nguyen
2018-10-03 16:45 ` Duy Nguyen
2018-10-04 21:42 ` [RFC PATCH] " Ævar Arnfjörð Bjarmason
2018-10-05 12:05 ` Derrick Stolee
2018-10-05 13:05 ` Ævar Arnfjörð Bjarmason
2018-10-05 13:45 ` Derrick Stolee
2018-10-05 14:04 ` Ævar Arnfjörð Bjarmason
2018-10-05 19:21 ` Jeff King
2018-10-05 19:41 ` Derrick Stolee
2018-10-05 19:47 ` Jeff King
2018-10-05 20:00 ` Derrick Stolee
2018-10-05 20:02 ` Jeff King
2018-10-05 20:01 ` Ævar Arnfjörð Bjarmason
2018-10-05 20:09 ` Jeff King
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