From: Jonathan Nieder <jrnieder@gmail.com> To: Junio C Hamano <gitster@pobox.com> Cc: Ben Peart <peartben@gmail.com>, git@vger.kernel.org, pclouds@gmail.com, Ben Peart <benpeart@microsoft.com>, jonathantanmy@google.com Subject: [PATCH 4/5] index: make index.threads=true enable ieot and eoie Date: Mon, 19 Nov 2018 22:14:26 -0800 Message-ID: <20181120061426.GE144753@google.com> (raw) In-Reply-To: <20181120060920.GA144753@google.com> If a user explicitly sets [index] threads = true to read the index using multiple threads, ensure that index writes include the offset table by default to make that possible. This ensures that the user's intent of turning on threading is respected. In other words, permit the following configurations: - index.threads and index.recordOffsetTable unspecified: do not write the offset table yet (to avoid alarming the user with "ignoring IEOT extension" messages when an older version of Git accesses the repository) but do make use of multiple threads to read the index if the supporting offset table is present. This can also be requested explicitly by setting index.threads=true, 0, or >1 and index.recordOffsetTable=false. - index.threads=false or 1: do not write the offset table, and do not make use of the offset table. One can set index.recordOffsetTable=false as well, to be more explicit. - index.threads=true, 0, or >1 and index.recordOffsetTable unspecified: write the offset table and make use of threads at read time. This can also be requested by setting index.threads=true, 0, >1, or unspecified and index.recordOffsetTable=true. Fortunately the complication is temporary: once most Git installations have upgraded to a version with support for the IEOT and EOIE extensions, we can flip the defaults for index.recordEndOfIndexEntries and index.recordOffsetTable to true and eliminate the settings. Helped-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> --- New, based on Ben Peart's feedback. Turned out simpler than I feared --- thanks, Ben, for pushing for this. Documentation/config/index.txt | 6 ++++-- config.c | 17 ++++++++++------- config.h | 2 +- read-cache.c | 23 +++++++++++++++++------ 4 files changed, 32 insertions(+), 16 deletions(-) diff --git a/Documentation/config/index.txt b/Documentation/config/index.txt index de44183235..f181503041 100644 --- a/Documentation/config/index.txt +++ b/Documentation/config/index.txt @@ -3,14 +3,16 @@ index.recordEndOfIndexEntries:: Entry" section. This reduces index load time on multiprocessor machines but produces a message "ignoring EOIE extension" when reading the index using Git versions before 2.20. Defaults to - 'false'. + 'true' if index.threads has been explicitly enabled, 'false' + otherwise. index.recordOffsetTable:: Specifies whether the index file should include an "Index Entry Offset Table" section. This reduces index load time on multiprocessor machines but produces a message "ignoring IEOT extension" when reading the index using Git versions before 2.20. - Defaults to 'false'. + Defaults to 'true' if index.threads has been explicitly enabled, + 'false' otherwise. index.threads:: Specifies the number of threads to spawn when loading the index. diff --git a/config.c b/config.c index 04286f7717..ff521eb27a 100644 --- a/config.c +++ b/config.c @@ -2294,22 +2294,25 @@ int git_config_get_fsmonitor(void) return 0; } -int git_config_get_index_threads(void) +int git_config_get_index_threads(int *dest) { - int is_bool, val = 0; + int is_bool, val; val = git_env_ulong("GIT_TEST_INDEX_THREADS", 0); - if (val) - return val; + if (val) { + *dest = val; + return 0; + } if (!git_config_get_bool_or_int("index.threads", &is_bool, &val)) { if (is_bool) - return val ? 0 : 1; + *dest = val ? 0 : 1; else - return val; + *dest = val; + return 0; } - return 0; /* auto */ + return 1; } NORETURN diff --git a/config.h b/config.h index a06027e69b..ee5d3fa7b4 100644 --- a/config.h +++ b/config.h @@ -246,11 +246,11 @@ extern int git_config_get_bool(const char *key, int *dest); extern int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest); extern int git_config_get_maybe_bool(const char *key, int *dest); extern int git_config_get_pathname(const char *key, const char **dest); +extern int git_config_get_index_threads(int *dest); extern int git_config_get_untracked_cache(void); extern int git_config_get_split_index(void); extern int git_config_get_max_percent_split_change(void); extern int git_config_get_fsmonitor(void); -extern int git_config_get_index_threads(void); /* This dies if the configured or default date is in the future */ extern int git_config_get_expiry(const char *key, const char **output); diff --git a/read-cache.c b/read-cache.c index 83d24357a6..002ed2c1e4 100644 --- a/read-cache.c +++ b/read-cache.c @@ -2176,7 +2176,8 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist) src_offset = sizeof(*hdr); - nr_threads = git_config_get_index_threads(); + if (git_config_get_index_threads(&nr_threads)) + nr_threads = 1; /* TODO: does creating more threads than cores help? */ if (!nr_threads) { @@ -2695,7 +2696,13 @@ static int record_eoie(void) if (!git_config_get_bool("index.recordendofindexentries", &val)) return val; - return 0; + + /* + * As a convenience, the end of index entries extension + * used for threading is written by default if the user + * explicitly requested threaded index reads. + */ + return !git_config_get_index_threads(&val) && val != 1; } static int record_ieot(void) @@ -2704,7 +2711,13 @@ static int record_ieot(void) if (!git_config_get_bool("index.recordoffsettable", &val)) return val; - return 0; + + /* + * As a convenience, the offset table used for threading is + * written by default if the user explicitly requested + * threaded index reads. + */ + return !git_config_get_index_threads(&val) && val != 1; } /* @@ -2765,9 +2778,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile, if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0) return -1; - if (HAVE_THREADS) - nr_threads = git_config_get_index_threads(); - else + if (!HAVE_THREADS || git_config_get_index_threads(&nr_threads)) nr_threads = 1; if (nr_threads != 1 && record_ieot()) { -- 2.20.0.rc0.387.gc7a69e6b6c
next prev parent reply other threads:[~2018-11-20 6:14 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 ` [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 ` Jonathan Nieder [this message] 2018-11-20 13:24 ` [PATCH 4/5] index: make index.threads=true enable ieot and eoie 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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