From: Alex Gramiak <agrambot@gmail.com>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: emacs-devel@gnu.org
Subject: Re: Using __builtin_expect (likely/unlikely macros)
Date: Sun, 14 Apr 2019 21:11:09 -0600 [thread overview]
Message-ID: <875zrgt12q.fsf@gmail.com> (raw)
In-Reply-To: <cee59ed0-99bc-d059-ee83-5e3099cecbd8@cs.ucla.edu> (Paul Eggert's message of "Sun, 14 Apr 2019 18:18:13 -0700")
Paul Eggert <eggert@cs.ucla.edu> writes:
> Alex Gramiak wrote:
>> the likely/unlikely
>> macros are a nice way to indicate that a branch is exceedingly
>> rare/common.
>
> The cost (in making the C code harder to read, write and maintain) so often
> exceeds that benefit that I'd rather avoid these macros unless there's a good
> performance case for putting them in.
I doubt that any performance benefit would be noticeable, at least
without some microbenchmarks that I don't have.
Though I don't think that these macros, used sparingly around code such
as emacs_abort, would make it harder to read/write/maintain. I'm
certainly not suggesting to throw them around without care.
Still, I understand the resistance to include them.
next prev parent reply other threads:[~2019-04-15 3:11 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-15 0:15 Using __builtin_expect (likely/unlikely macros) Alex Gramiak
2019-04-15 1:18 ` Paul Eggert
2019-04-15 3:11 ` Alex Gramiak [this message]
2019-04-15 4:41 ` Paul Eggert
2019-04-16 0:16 ` Alex Gramiak
2019-04-16 2:34 ` Eli Zaretskii
2019-04-16 5:33 ` Alex Gramiak
2019-04-16 15:23 ` Eli Zaretskii
2019-04-16 15:47 ` Alex Gramiak
2019-04-16 3:42 ` Paul Eggert
2019-04-16 13:05 ` Stefan Monnier
2019-04-16 15:22 ` Paul Eggert
2019-04-16 16:10 ` Alex Gramiak
2019-04-16 17:54 ` Paul Eggert
2019-04-16 20:50 ` Alex Gramiak
2019-04-16 21:11 ` Alex Gramiak
2019-04-16 21:27 ` Stefan Monnier
2019-04-16 21:27 ` Konstantin Kharlamov
2019-04-18 8:25 ` Paul Eggert
2019-04-18 8:43 ` Konstantin Kharlamov
2019-04-18 13:47 ` Andy Moreton
2019-04-18 17:27 ` Paul Eggert
2019-04-18 17:56 ` Andy Moreton
2019-04-18 19:32 ` Paul Eggert
2019-04-19 13:45 ` Alex Gramiak
2019-04-19 13:58 ` Konstantin Kharlamov
2019-04-19 14:45 ` Alex Gramiak
2019-04-19 17:33 ` Paul Eggert
2019-04-19 20:53 ` Alex Gramiak
2019-04-20 0:05 ` Alan Mackenzie
2019-04-20 0:42 ` Paul Eggert
2019-04-20 19:46 ` Alan Mackenzie
2019-04-20 15:29 ` Andy Moreton
2019-04-20 15:57 ` Paul Eggert
2019-04-20 16:03 ` Eli Zaretskii
2019-04-20 16:11 ` Paul Eggert
2019-04-20 16:18 ` Eli Zaretskii
2019-04-20 16:57 ` Paul Eggert
2019-04-20 17:22 ` Eli Zaretskii
2019-04-20 19:13 ` Paul Eggert
2019-04-20 16:28 ` Óscar Fuentes
2019-04-20 18:58 ` Paul Eggert
2019-04-20 19:35 ` Óscar Fuentes
2019-04-20 22:54 ` Paul Eggert
2020-04-15 3:14 ` John Carter
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