From: Duy Nguyen <pclouds@gmail.com> To: Ben Peart <peartben@gmail.com> Cc: Junio C Hamano <gitster@pobox.com>, Ben Peart <Ben.Peart@microsoft.com>, Git Mailing List <git@vger.kernel.org> Subject: Re: [PATCH v1] read-cache: speed up index load through parallelization Date: Fri, 24 Aug 2018 17:37:20 +0200 Message-ID: <CACsJy8CUPGUhR3girstdqD6YVxOQ6_xE+gacT98KXgqOSPz0dw@mail.gmail.com> (raw) In-Reply-To: <4c70ea50-5b43-8696-3c46-cf3d658a0ef8@gmail.com> Since we're cutting corners to speed things up, could you try something like this? I notice that reading v4 is significantly slower than v2 and apparently strlen() (at least from glibc) is much cleverer and at least gives me a few percentage time saving. diff --git a/read-cache.c b/read-cache.c index 7b1354d759..d10cccaed0 100644 --- a/read-cache.c +++ b/read-cache.c @@ -1755,8 +1755,7 @@ static unsigned long expand_name_field(struct strbuf *name, const char *cp_) if (name->len < len) die("malformed name field in the index"); strbuf_remove(name, name->len - len, len); - for (ep = cp; *ep; ep++) - ; /* find the end */ + ep = cp + strlen(cp); strbuf_add(name, cp, ep - cp); return (const char *)ep + 1 - cp_; } On Thu, Aug 23, 2018 at 10:36 PM Ben Peart <peartben@gmail.com> wrote: > > Nice to see this done without a new index extension that records > > offsets, so that we can load existing index files in parallel. > > > > Yes, I prefer this simpler model as well. I wasn't sure it would > produce a significant improvement given the primary thread still has to > run through the variable length cache entries but was pleasantly surprised. Out of curiosity, how much time saving could we gain by recording offsets as an extension (I assume we need, like 4 offsets if the system has 4 cores)? Much much more than this simpler model (which may justify the complexity) or just "meh" compared to this? -- Duy
next prev parent reply other threads:[~2018-08-24 15:37 UTC|newest] Thread overview: 199+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-08-23 15:41 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 [this message] 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 ` [PATCH v6 0/7] speed up index load through parallelization Junio C Hamano 2018-09-27 17:13 ` 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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