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Re: Using __builtin_expect (likely/unlikely macros)
From: |
Alex Gramiak |
Subject: |
Re: Using __builtin_expect (likely/unlikely macros) |
Date: |
Sun, 14 Apr 2019 21:11:09 -0600 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) |
Paul Eggert <address@hidden> 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.
- Using __builtin_expect (likely/unlikely macros), Alex Gramiak, 2019/04/14
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/14
- Re: Using __builtin_expect (likely/unlikely macros),
Alex Gramiak <=
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/15
- Re: Using __builtin_expect (likely/unlikely macros), Alex Gramiak, 2019/04/15
- Re: Using __builtin_expect (likely/unlikely macros), Eli Zaretskii, 2019/04/15
- Re: Using __builtin_expect (likely/unlikely macros), Alex Gramiak, 2019/04/16
- Re: Using __builtin_expect (likely/unlikely macros), Eli Zaretskii, 2019/04/16
- Re: Using __builtin_expect (likely/unlikely macros), Alex Gramiak, 2019/04/16
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/15
- Re: Using __builtin_expect (likely/unlikely macros), Stefan Monnier, 2019/04/16
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/16
- Re: Using __builtin_expect (likely/unlikely macros), Alex Gramiak, 2019/04/16