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From: Junio C Hamano <gitster@pobox•com>
To: Stefan Beller <sbeller@google•com>
Cc: "git\@vger.kernel.org" <git@vger•kernel.org>,
	Brandon Williams <bmwill@google•com>,
	Duy Nguyen <pclouds@gmail•com>
Subject: Re: [PATCH 28/36] attr: keep attr stack for each check
Date: Mon, 24 Oct 2016 13:29:52 -0700	[thread overview]
Message-ID: <xmqqlgxd32yn.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <CAGZ79kZ_7eG4uCXwyg0F=-hjmuT1dCAATSRnY293qkNC6siM5Q@mail.gmail.com> (Stefan Beller's message of "Mon, 24 Oct 2016 12:32:32 -0700")

Stefan Beller <sbeller@google•com> writes:

> I looked for a platform independent way to get a thread id as a natural
> number, i.e. I want to get 1,2,3,... such that I could have just added
> list/array of attr stacks to each check, which would be the
> <check, thread> tuple you envision.
>
> However I think we do not really need it to be per check.  If we had
> an easy portable way of getting such a thread id, I would have implemented
> a list of stacks per thread first. (Because each thread only looks at one
> check at a time.)

It seems that by "list of stacks per thread", you mean "there is a
list of stacks, each thread uses one and only element of that list",
but I do not think it would be desirable.

"Each thread only looks at one check at a time" is false.  For
example, "write_archive_entry()" would use one check that is
specific to "git archive" to learn about "export-ignore" and
"export-subst" attributes, while letting convert_to_write_tree()
called via sha1_file_to_archive() called via write_entry() method
(i.e. write_tar_entry() or write_zip_entry()) to use a separate
check that is specific to the convert.c API.

>> With manipulation of attr stack protected with a single Big
>> Attributes Lock, this should be safe.  It may not perform very well
>> when used by multiple threads, though ;-)
>
> I agree. So maybe it is not really a good fit for general consumption yet.

I would still think it is a good first step.  It may already be
thread-safe, but may not be thread-ready from performance point of
view.  IOW, this would not yet help an attempt to make the callers
faster by making them multi-threaded.


  reply	other threads:[~2016-10-24 20:29 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-22 23:31 [PATCHv2 00/36] Revamping the attr subsystem! Stefan Beller
2016-10-22 23:31 ` [PATCH 01/36] commit.c: use strchrnul() to scan for one line Stefan Beller
2016-10-22 23:31 ` [PATCH 02/36] attr.c: " Stefan Beller
2016-10-22 23:31 ` [PATCH 03/36] attr.c: update a stale comment on "struct match_attr" Stefan Beller
2016-10-22 23:31 ` [PATCH 04/36] attr.c: explain the lack of attr-name syntax check in parse_attr() Stefan Beller
2016-10-22 23:31 ` [PATCH 05/36] attr.c: complete a sentence in a comment Stefan Beller
2016-10-22 23:31 ` [PATCH 06/36] attr.c: mark where #if DEBUG ends more clearly Stefan Beller
2016-10-22 23:31 ` [PATCH 07/36] attr.c: simplify macroexpand_one() Stefan Beller
2016-10-22 23:31 ` [PATCH 08/36] attr.c: tighten constness around "git_attr" structure Stefan Beller
2016-10-22 23:31 ` [PATCH 09/36] attr.c: plug small leak in parse_attr_line() Stefan Beller
2016-10-22 23:31 ` [PATCH 10/36] attr: rename function and struct related to checking attributes Stefan Beller
2016-10-22 23:32 ` [PATCH 11/36] attr: (re)introduce git_check_attr() and struct git_attr_check Stefan Beller
2016-10-22 23:32 ` [PATCH 12/36] attr: convert git_all_attrs() to use "struct git_attr_check" Stefan Beller
2016-10-22 23:32 ` [PATCH 13/36] attr: convert git_check_attrs() callers to use the new API Stefan Beller
2016-10-22 23:32 ` [PATCH 14/36] attr: retire git_check_attrs() API Stefan Beller
2016-10-22 23:32 ` [PATCH 15/36] attr: add counted string version of git_check_attr() Stefan Beller
2016-10-22 23:32 ` [PATCH 16/36] attr: add counted string version of git_attr() Stefan Beller
2016-10-22 23:32 ` [PATCH 17/36] attr: expose validity check for attribute names Stefan Beller
2016-10-23 15:07   ` Ramsay Jones
2016-10-24 21:07     ` Stefan Beller
2016-10-27 20:57       ` Stefan Beller
2016-10-26 21:20     ` [PATCH] attr: expose error reporting function for invalid " Stefan Beller
2016-10-22 23:32 ` [PATCH 18/36] attr: support quoting pathname patterns in C style Stefan Beller
2016-10-22 23:32 ` [PATCH 19/36] attr.c: add push_stack() helper Stefan Beller
2016-10-22 23:32 ` [PATCH 20/36] attr.c: pass struct git_attr_check down the callchain Stefan Beller
2016-10-22 23:32 ` [PATCH 21/36] attr.c: rename a local variable check Stefan Beller
2016-10-22 23:32 ` [PATCH 22/36] attr.c: correct ugly hack for git_all_attrs() Stefan Beller
2016-10-22 23:32 ` [PATCH 23/36] attr.c: introduce empty_attr_check_elems() Stefan Beller
2016-10-22 23:32 ` [PATCH 24/36] attr.c: always pass check[] to collect_some_attrs() Stefan Beller
2016-10-22 23:32 ` [PATCH 25/36] attr.c: outline the future plans by heavily commenting Stefan Beller
2016-10-22 23:32 ` [PATCH 26/36] attr: make git_check_attr_counted static Stefan Beller
2016-10-22 23:32 ` [PATCH 27/36] attr: convert to new threadsafe API Stefan Beller
2016-10-24 18:55   ` Junio C Hamano
2016-10-24 19:18     ` Stefan Beller
2016-10-26 14:06       ` Duy Nguyen
2016-10-26  8:52   ` Johannes Schindelin
2016-10-26  9:35     ` Simon Ruderich
2016-10-26 12:15       ` Jeff King
2016-10-26 19:51         ` Stefan Beller
2016-10-26 20:20           ` Jeff King
2016-10-26 20:25           ` Johannes Sixt
2016-10-26 20:26             ` Jeff King
2016-10-26 20:40               ` Johannes Sixt
2016-10-26 20:46                 ` Stefan Beller
2016-10-26 22:41                   ` [PATCHv2 1/2] " Stefan Beller
2016-10-26 23:14                     ` Junio C Hamano
2016-10-27  0:08                       ` Stefan Beller
2016-10-27  0:16                         ` Junio C Hamano
2016-10-27  0:22                           ` Stefan Beller
2016-10-27  0:50                             ` Junio C Hamano
2016-10-27  0:49                     ` Junio C Hamano
2016-10-27  2:19                       ` Stefan Beller
2016-10-27  4:13                         ` Junio C Hamano
2016-10-27  5:44                           ` Junio C Hamano
2016-10-27 22:15                             ` [PATCH] " Stefan Beller
2016-10-28  8:55                               ` Johannes Schindelin
2016-10-28 17:20                               ` Junio C Hamano
2016-10-28 17:30                                 ` Junio C Hamano
2016-10-28 18:16                               ` Johannes Sixt
2016-10-26 20:43               ` [PATCH 27/36] " Stefan Beller
2016-10-26 13:52   ` Duy Nguyen
2016-10-22 23:32 ` [PATCH 28/36] attr: keep attr stack for each check Stefan Beller
2016-10-23 15:10   ` Ramsay Jones
2016-10-26 23:10     ` Stefan Beller
2016-10-24 19:07   ` Junio C Hamano
2016-10-24 19:32     ` Stefan Beller
2016-10-24 20:29       ` Junio C Hamano [this message]
2016-10-22 23:32 ` [PATCH 29/36] Documentation: fix a typo Stefan Beller
2016-10-22 23:32 ` [PATCH 30/36] pathspec: move long magic parsing out of prefix_pathspec Stefan Beller
2016-10-22 23:32 ` [PATCH 31/36] pathspec: move prefix check out of the inner loop Stefan Beller
2016-10-22 23:32 ` [PATCH 32/36] pathspec: allow querying for attributes Stefan Beller
2016-10-26 13:33   ` Duy Nguyen
2016-10-27 21:32     ` Stefan Beller
2016-10-27 18:29   ` Junio C Hamano
2016-11-09  9:45     ` Duy Nguyen
2016-11-09 18:08       ` Stefan Beller
2016-11-09 22:25         ` Junio C Hamano
2016-10-22 23:32 ` [PATCH 33/36] pathspec: allow escaped query values Stefan Beller
2016-10-22 23:32 ` [PATCH 34/36] submodule update: add `--init-default-path` switch Stefan Beller
2016-10-22 23:32 ` [PATCH 35/36] clone: add --init-submodule=<pathspec> switch Stefan Beller
2016-10-22 23:32 ` [PATCH 36/36] completion: clone can initialize specific submodules Stefan Beller

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