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From: Ben Peart <peartben@gmail.com>
To: Jonathan Nieder <jrnieder@gmail.com>
Cc: git@vger.kernel.org, gitster@pobox.com, pclouds@gmail.com,
	Ben Peart <benpeart@microsoft.com>
Subject: Re: [PATCH 2/3] ieot: default to not writing IEOT section
Date: Tue, 13 Nov 2018 10:22:44 -0500
Message-ID: <f2f8cec8-d770-a1e9-b5a1-83653575122e@gmail.com> (raw)
In-Reply-To: <20181113003938.GC170017@google.com>



On 11/12/2018 7:39 PM, Jonathan Nieder wrote:
> As with EOIE, popular versions of Git do not support the new IEOT
> extension yet.  When accessing a Git repository written by a more
> modern version of Git, they correctly ignore the unrecognized section,
> but in the process they loudly warn
> 
> 	ignoring IEOT extension
> 
> resulting in confusion for users.  Introduce the index extension more
> gently by not writing it yet in this first version with support for
> it.  Soon, once sufficiently many users are running a modern version
> of Git, we can flip the default so users benefit from this index
> extension by default.
> 
> Introduce a '[index] recordOffsetTable' configuration variable to
> control whether the new index extension is written.
> 

Why introduce a new setting to disable writing the IEOT extension 
instead of just using the existing index.threads setting?  If 
index.threads=1 then the IEOT extension isn't written which (I believe) 
will accomplish the same goal.

> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
>   Documentation/config.txt |  7 +++++++
>   read-cache.c             | 11 ++++++++++-
>   2 files changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index d702379db4..cc66fb7de3 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -2195,6 +2195,13 @@ index.recordEndOfIndexEntries::
>   	reading the index using Git versions before 2.20. Defaults to
>   	'false'.
>   
> +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'.
> +
>   index.threads::
>   	Specifies the number of threads to spawn when loading the index.
>   	This is meant to reduce index load time on multiprocessor machines.
> diff --git a/read-cache.c b/read-cache.c
> index 4bfe93c4c2..290bd54708 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -2707,6 +2707,15 @@ static int record_eoie(void)
>   	return 0;
>   }
>   
> +static int record_ieot(void)
> +{
> +	int val;
> +
> +	if (!git_config_get_bool("index.recordoffsettable", &val))
> +		return val;
> +	return 0;
> +}
> +
>   /*
>    * On success, `tempfile` is closed. If it is the temporary file
>    * of a `struct lock_file`, we will therefore effectively perform
> @@ -2767,7 +2776,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
>   
>   #ifndef NO_PTHREADS
>   	nr_threads = git_config_get_index_threads();
> -	if (nr_threads != 1) {
> +	if (nr_threads != 1 && record_ieot()) {
>   		int ieot_blocks, cpus;
>   
>   		/*
> 

  parent reply index

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 [this message]
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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