From: Junio C Hamano <gitster@pobox.com>
To: Ben Peart <peartben@gmail.com>
Cc: git@vger.kernel.org, pclouds@gmail.com,
Ben Peart <benpeart@microsoft.com>
Subject: Re: [PATCH v6 0/7] speed up index load through parallelization
Date: Wed, 26 Sep 2018 15:06:57 -0700 [thread overview]
Message-ID: <xmqq5zyrkj5q.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180926195442.1380-1-benpeart@microsoft.com> (Ben Peart's message of "Wed, 26 Sep 2018 15:54:35 -0400")
Ben Peart <peartben@gmail.com> writes:
> Base Ref: master
> Web-Diff: https://github.com/benpeart/git/commit/a0300882d4
> Checkout: git fetch https://github.com/benpeart/git read-index-multithread-v6 && git checkout a0300882d4
>
>
> This iteration brings back the Index Entry Offset Table (IEOT) extension
> which enables us to multi-thread the cache entry parsing without having
> the primary thread have to scan all the entries first. In cases where the
> cache entry parsing is the most expensive part, this yields some additional
> savings.
Nice.
> Test w/100,000 files Baseline Optimize V4 Extensions Entries
> ----------------------------------------------------------------------------
> 0002.1: read_cache 22.36 18.74 -16.2% 18.64 -16.6% 12.63 -43.5%
>
> Test w/1,000,000 files Baseline Optimize V4 Extensions Entries
> -----------------------------------------------------------------------------
> 0002.1: read_cache 304.40 270.70 -11.1% 195.50 -35.8% 204.82 -32.7%
>
> Note that on the 1,000,000 files case, multi-threading the cache entry parsing
> does not yield a performance win. This is because the cost to parse the
> index extensions in this repo, far outweigh the cost of loading the cache
> entries.
> ...
> The high cost of parsing the index extensions is driven by the cache tree
> and the untracked cache extensions. As this is currently the longest pole,
> any reduction in this time will reduce the overall index load times so is
> worth further investigation in another patch series.
Interesting.
> One option would be to load each extension on a separate thread but I
> believe that is overkill for the vast majority of repos. Instead, some
> optimization of the loading code for these two extensions is probably worth
> looking into as a quick examination shows that the bulk of the time for both
> of them is spent in xcalloc().
Thanks. Looking forward to block some quality time off to read this
through, but from the cursory look (read: diff between the previous
round), this looks quite promising.
next prev parent reply other threads:[~2018-09-26 22:07 UTC|newest]
Thread overview: 199+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-23 15:41 [PATCH v1] read-cache: speed up index load through parallelization Ben Peart
2018-08-23 17:31 ` Stefan Beller
2018-08-23 19:44 ` Ben Peart
2018-08-24 18:40 ` Duy Nguyen
2018-08-28 14:53 ` Ben Peart
2018-08-23 18:06 ` Junio C Hamano
2018-08-23 20:33 ` Ben Peart
2018-08-24 15:37 ` Duy Nguyen
2018-08-24 15:57 ` Duy Nguyen
2018-08-24 17:28 ` Ben Peart
2018-08-25 6:44 ` [PATCH] read-cache.c: optimize reading index format v4 Nguyễn Thái Ngọc Duy
2018-08-27 19:36 ` Junio C Hamano
2018-08-28 19:25 ` Duy Nguyen
2018-08-28 23:54 ` Ben Peart
2018-08-29 17:14 ` Junio C Hamano
2018-09-04 16:08 ` Duy Nguyen
2018-09-02 13:19 ` [PATCH v2 0/1] " Nguyễn Thái Ngọc Duy
2018-09-02 13:19 ` [PATCH v2 1/1] read-cache.c: " Nguyễn Thái Ngọc Duy
2018-09-04 18:58 ` Junio C Hamano
2018-09-04 19:31 ` Junio C Hamano
2018-08-24 18:20 ` [PATCH v1] read-cache: speed up index load through parallelization Duy Nguyen
2018-08-24 18:40 ` Ben Peart
2018-08-24 19:00 ` Duy Nguyen
2018-08-24 19:57 ` Ben Peart
2018-08-29 15:25 ` [PATCH v2 0/3] " Ben Peart
2018-08-29 15:25 ` [PATCH v2 1/3] " Ben Peart
2018-08-29 17:14 ` Junio C Hamano
2018-08-29 21:35 ` Ben Peart
2018-09-03 19:16 ` Duy Nguyen
2018-08-29 15:25 ` [PATCH v2 2/3] read-cache: load cache extensions on worker thread Ben Peart
2018-08-29 17:12 ` Junio C Hamano
2018-08-29 21:42 ` Ben Peart
2018-08-29 22:19 ` Junio C Hamano
2018-09-03 19:21 ` Duy Nguyen
2018-09-03 19:27 ` Duy Nguyen
2018-08-29 15:25 ` [PATCH v2 3/3] read-cache: micro-optimize expand_name_field() to speed up V4 index parsing Ben Peart
2018-09-06 21:03 ` [PATCH v3 0/4] read-cache: speed up index load through parallelization Ben Peart
2018-09-06 21:03 ` [PATCH v3 1/4] read-cache: optimize expand_name_field() to speed up V4 index parsing Ben Peart
2018-09-06 21:03 ` [PATCH v3 2/4] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-09-07 17:55 ` Junio C Hamano
2018-09-07 20:23 ` Ben Peart
2018-09-08 6:29 ` Martin Ågren
2018-09-08 14:03 ` Ben Peart
2018-09-08 17:08 ` Martin Ågren
2018-09-06 21:03 ` [PATCH v3 3/4] read-cache: load cache extensions on a worker thread Ben Peart
2018-09-07 21:10 ` Junio C Hamano
2018-09-08 14:56 ` Ben Peart
2018-09-06 21:03 ` [PATCH v3 4/4] read-cache: speed up index load through parallelization Ben Peart
2018-09-07 4:16 ` Torsten Bögershausen
2018-09-07 13:43 ` Ben Peart
2018-09-07 17:21 ` [PATCH v3 0/4] " Junio C Hamano
2018-09-07 18:31 ` Ben Peart
2018-09-08 13:18 ` Duy Nguyen
2018-09-11 23:26 ` [PATCH v4 0/5] " Ben Peart
2018-09-11 23:26 ` [PATCH v4 1/5] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-09-11 23:26 ` [PATCH v4 2/5] read-cache: load cache extensions on a worker thread Ben Peart
2018-09-11 23:26 ` [PATCH v4 3/5] read-cache: speed up index load through parallelization Ben Peart
2018-09-11 23:26 ` [PATCH v4 4/5] read-cache.c: optimize reading index format v4 Ben Peart
2018-09-11 23:26 ` [PATCH v4 5/5] read-cache: clean up casting and byte decoding Ben Peart
2018-09-12 14:34 ` [PATCH v4 0/5] read-cache: speed up index load through parallelization Ben Peart
2018-09-12 16:18 ` [PATCH v5 " Ben Peart
2018-09-12 16:18 ` [PATCH v5 1/5] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-09-13 22:44 ` Junio C Hamano
2018-09-15 10:02 ` Duy Nguyen
2018-09-17 14:54 ` Ben Peart
2018-09-17 16:05 ` Duy Nguyen
2018-09-17 17:31 ` Junio C Hamano
2018-09-17 17:38 ` Duy Nguyen
2018-09-17 19:08 ` Junio C Hamano
2018-09-12 16:18 ` [PATCH v5 2/5] read-cache: load cache extensions on a worker thread Ben Peart
2018-09-15 10:22 ` Duy Nguyen
2018-09-15 10:24 ` Duy Nguyen
2018-09-17 16:38 ` Ben Peart
2018-09-15 16:23 ` Duy Nguyen
2018-09-17 17:19 ` Junio C Hamano
2018-09-17 16:26 ` Ben Peart
2018-09-17 16:45 ` Duy Nguyen
2018-09-17 21:32 ` Junio C Hamano
2018-09-12 16:18 ` [PATCH v5 3/5] read-cache: load cache entries on worker threads Ben Peart
2018-09-15 10:31 ` Duy Nguyen
2018-09-17 17:25 ` Ben Peart
2018-09-15 11:07 ` Duy Nguyen
2018-09-15 11:09 ` Duy Nguyen
2018-09-17 18:52 ` Ben Peart
2018-09-15 11:29 ` Duy Nguyen
2018-09-12 16:18 ` [PATCH v5 4/5] read-cache.c: optimize reading index format v4 Ben Peart
2018-09-12 16:18 ` [PATCH v5 5/5] read-cache: clean up casting and byte decoding Ben Peart
2018-09-26 19:54 ` [PATCH v6 0/7] speed up index load through parallelization Ben Peart
2018-09-26 19:54 ` [PATCH v6 1/7] read-cache.c: optimize reading index format v4 Ben Peart
2018-09-26 19:54 ` [PATCH v6 2/7] read-cache: clean up casting and byte decoding Ben Peart
2018-09-26 19:54 ` [PATCH v6 3/7] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-09-28 0:19 ` SZEDER Gábor
2018-09-28 18:38 ` Ben Peart
2018-09-29 0:51 ` SZEDER Gábor
2018-09-29 5:45 ` Duy Nguyen
2018-09-29 18:24 ` Junio C Hamano
2018-09-26 19:54 ` [PATCH v6 4/7] config: add new index.threads config setting Ben Peart
2018-09-28 0:26 ` SZEDER Gábor
2018-09-28 13:39 ` Ben Peart
2018-09-28 17:07 ` Junio C Hamano
2018-09-28 19:41 ` Ben Peart
2018-09-28 20:30 ` Ramsay Jones
2018-09-28 22:15 ` Junio C Hamano
2018-10-01 13:17 ` Ben Peart
2018-10-01 15:06 ` SZEDER Gábor
2018-09-26 19:54 ` [PATCH v6 5/7] read-cache: load cache extensions on a worker thread Ben Peart
2018-09-26 19:54 ` [PATCH v6 6/7] ieot: add Index Entry Offset Table (IEOT) extension Ben Peart
2018-09-26 19:54 ` [PATCH v6 7/7] read-cache: load cache entries on worker threads Ben Peart
2018-09-26 22:06 ` Junio C Hamano [this message]
2018-09-27 17:13 ` [PATCH v6 0/7] speed up index load through parallelization Duy Nguyen
2018-10-01 13:45 ` [PATCH v7 " Ben Peart
2018-10-01 13:45 ` [PATCH v7 1/7] read-cache.c: optimize reading index format v4 Ben Peart
2018-10-01 13:45 ` [PATCH v7 2/7] read-cache: clean up casting and byte decoding Ben Peart
2018-10-01 15:10 ` Duy Nguyen
2018-10-01 13:45 ` [PATCH v7 3/7] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-10-01 15:17 ` SZEDER Gábor
2018-10-02 14:34 ` Ben Peart
2018-10-01 15:30 ` Duy Nguyen
2018-10-02 15:13 ` Ben Peart
2018-10-01 13:45 ` [PATCH v7 4/7] config: add new index.threads config setting Ben Peart
2018-10-01 13:45 ` [PATCH v7 5/7] read-cache: load cache extensions on a worker thread Ben Peart
2018-10-01 15:50 ` Duy Nguyen
2018-10-02 15:00 ` Ben Peart
2018-10-01 13:45 ` [PATCH v7 6/7] ieot: add Index Entry Offset Table (IEOT) extension Ben Peart
2018-10-01 16:27 ` Duy Nguyen
2018-10-02 16:34 ` Ben Peart
2018-10-02 17:02 ` Duy Nguyen
2018-10-01 13:45 ` [PATCH v7 7/7] read-cache: load cache entries on worker threads Ben Peart
2018-10-01 17:09 ` Duy Nguyen
2018-10-02 19:09 ` Ben Peart
2018-10-10 15:59 ` [PATCH v8 0/7] speed up index load through parallelization Ben Peart
2018-10-10 15:59 ` [PATCH v8 1/7] read-cache.c: optimize reading index format v4 Ben Peart
2018-10-10 15:59 ` [PATCH v8 2/7] read-cache: clean up casting and byte decoding Ben Peart
2018-10-10 15:59 ` [PATCH v8 3/7] eoie: add End of Index Entry (EOIE) extension Ben Peart
2018-10-10 15:59 ` [PATCH v8 4/7] config: add new index.threads config setting Ben Peart
2018-10-10 15:59 ` [PATCH v8 5/7] read-cache: load cache extensions on a worker thread Ben Peart
2018-10-10 15:59 ` [PATCH v8 6/7] ieot: add Index Entry Offset Table (IEOT) extension Ben Peart
2018-10-10 15:59 ` [PATCH v8 7/7] read-cache: load cache entries on worker threads Ben Peart
2018-10-19 16:11 ` Jeff King
2018-10-22 2:14 ` Junio C Hamano
2018-10-22 14:40 ` Ben Peart
2018-10-12 3:18 ` [PATCH v8 0/7] speed up index load through parallelization Junio C Hamano
2018-10-14 12:28 ` Duy Nguyen
2018-10-15 17:33 ` Ben Peart
2018-11-13 0:38 ` [PATCH 0/3] Avoid confusing messages from new index extensions (Re: [PATCH v8 0/7] speed up index load through parallelization) Jonathan Nieder
2018-11-13 0:39 ` [PATCH 1/3] eoie: default to not writing EOIE section Jonathan Nieder
2018-11-13 1:05 ` Junio C Hamano
2018-11-13 15:14 ` Ben Peart
2018-11-13 18:25 ` Jonathan Nieder
2018-11-14 1:36 ` Junio C Hamano
2018-11-15 0:19 ` Jonathan Nieder
2018-11-13 0:39 ` [PATCH 2/3] ieot: default to not writing IEOT section Jonathan Nieder
2018-11-13 0:58 ` Jonathan Tan
2018-11-13 1:09 ` Junio C Hamano
2018-11-13 1:12 ` Jonathan Nieder
2018-11-13 15:37 ` Duy Nguyen
2018-11-13 18:09 ` Jonathan Nieder
2018-11-13 15:22 ` Ben Peart
2018-11-13 18:18 ` Jonathan Nieder
2018-11-13 19:15 ` Ben Peart
2018-11-13 21:08 ` Jonathan Nieder
2018-11-14 18:09 ` Ben Peart
2018-11-15 0:05 ` Jonathan Nieder
2018-11-14 3:05 ` Junio C Hamano
2018-11-20 6:09 ` [PATCH v2 0/5] Avoid confusing messages from new index extensions Jonathan Nieder
2018-11-20 6:11 ` [PATCH 1/5] eoie: default to not writing EOIE section Jonathan Nieder
2018-11-20 13:06 ` Ben Peart
2018-11-20 13:21 ` SZEDER Gábor
2018-11-21 16:46 ` Jeff King
2018-11-22 0:47 ` Junio C Hamano
2018-11-20 15:01 ` Ben Peart
2018-11-20 6:12 ` [PATCH 2/5] ieot: default to not writing IEOT section Jonathan Nieder
2018-11-20 13:07 ` Ben Peart
2018-11-26 19:59 ` Stefan Beller
2018-11-26 21:47 ` Ben Peart
2018-11-26 22:02 ` Stefan Beller
2018-11-27 0:50 ` Junio C Hamano
2018-11-20 6:12 ` [PATCH 3/5] index: do not warn about unrecognized extensions Jonathan Nieder
2018-11-20 6:14 ` [PATCH 4/5] index: make index.threads=true enable ieot and eoie Jonathan Nieder
2018-11-20 13:24 ` Ben Peart
2018-11-20 6:15 ` [PATCH 5/5] index: offer advice for unknown index extensions Jonathan Nieder
2018-11-20 9:26 ` Ævar Arnfjörð Bjarmason
2018-11-20 13:30 ` Ben Peart
2018-11-21 0:22 ` Junio C Hamano
2018-11-21 0:39 ` Jonathan Nieder
2018-11-21 0:44 ` Jonathan Nieder
2018-11-21 5:01 ` Junio C Hamano
2018-11-21 5:04 ` Jonathan Nieder
2018-11-21 5:15 ` Junio C Hamano
2018-11-21 5:31 ` Junio C Hamano
2018-11-21 1:03 ` Jonathan Nieder
2018-11-21 4:23 ` Junio C Hamano
2018-11-21 4:57 ` Jonathan Nieder
2018-11-21 9:30 ` Ævar Arnfjörð Bjarmason
2018-11-13 0:40 ` [PATCH 3/3] index: do not warn about unrecognized extensions Jonathan Nieder
2018-11-13 1:10 ` Junio C Hamano
2018-11-13 15:25 ` Ben Peart
2018-11-14 3:24 ` Junio C Hamano
2018-11-14 18:19 ` Ben Peart
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