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From: Duy Nguyen <pclouds@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Stefan Beller <sbeller@google.com>,
	Git Mailing List <git@vger.kernel.org>,
	Brandon Williams <bmwill@google.com>
Subject: Re: [PATCH 32/36] pathspec: allow querying for attributes
Date: Wed, 9 Nov 2016 16:45:39 +0700	[thread overview]
Message-ID: <CACsJy8C2MLg4ncLBXXJGf+=mPF_rRoKs2vN6=+chZeNeXWZsbg@mail.gmail.com> (raw)
In-Reply-To: <xmqqzilp63yh.fsf@gitster.mtv.corp.google.com>

On Fri, Oct 28, 2016 at 1:29 AM, Junio C Hamano <gitster@pobox.com> wrote:
> The reason why I am bringing this up in this discussion thread on
> this patch is because I wonder if we would benefit by a similar
> "let's not do too involved things and be cheap by erring on the safe
> and lazy side" strategy in the call to ce_path_match() call made in
> this function to avoid making calls to the attr subsystem.
>
> In other words, would it help the system by either simplifying the
> processing done or reducing the cycle spent in preload_thread() if
> we could tell ce_path_match() "A pathspec we are checking may
> require not just the pattern to match but also attributes given to
> the path to satisfy the criteria, but for the purpose of preloading,
> pretend that the attribute satisfies the match criteria" (or
> "pretend that it does not match"), thereby not having to make any
> call into the attribute subsystem at all from this codepath?
>
> The strategy this round takes to make it unnecessary to punt
> preloading (i.e. dropping "pathspec: disable preload-index when
> attribute pathspec magic is in use" patch the old series had) is to
> make the attribute subsystem thread-safe.  But that thread-safety in
> the initial round is based on a single Big Attribute Lock, so it may
> turn out that the end result performs better for this codepath if we
> did not to make any call into the attribute subsystem.

It does sound good and I want to say "yes please do this", but is it
making pathspec api a bit more complex (to express "assume all
attr-related criteria match")? I guess we can have an api to simply
filter out attr-related magic (basically set attr_match_nr back to
zero) then pass a safe (but more relaxing) pathspec to the threaded
code. That would not add big maintenance burden.

> I am probably being two step ahead of ourselves by saying the above,
> which is just something to keep in mind as a possible solution if
> performance in this preload codepath becomes an issue when the
> pathspec has attributes match specified.
-- 
Duy

  reply	other threads:[~2016-11-09  9:46 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
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 [this message]
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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