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Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstr
From: |
Gemini Lasswell |
Subject: |
Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps. |
Date: |
Mon, 26 Nov 2018 17:07:07 -0800 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1.90 (gnu/linux) |
Alan Mackenzie <address@hidden> writes:
Hi Alan,
> Mainly because of EQ, the C macro corresponding to `eq'. In master, EQ
> just does a binary comparison between two Lisp_Objects, and that's it.
> In scratch/accurate-warning-pos, should that binary comparison fail, EQ
> additionally has to check the flag variable `symbols-with-pos-enabled'
> to see whether it needs to do any additional comparisons. Except while
> byte compiling, it won't, but the check of that variable is what is
> causing the slowdown.
I'm having trouble accepting that this is the problem.
When I hear a story about a C program, where adding an always failing
check of a boolean variable to it causes it to run slower by 15% or 20%,
then when I read the code I expect to find that variable check inside a
really tight loop with only a few other instructions besides the
variable check.
But Fforward_word is significantly slower in your branch and I can't
find any tight loops with an EQ in it. exec_byte_code might fit that
description, if you gave it a Lisp function with a loop that hammered on
'eq', but that doesn't describe fill-region-as-paragraph, which is 15%
slower. Could there be anything else causing a slowdown besides EQ?
>> Another related question: this work is for warnings, but will it
>> extend to having positions in backtraces?
>
> I hadn't actually got to thinking about that, but the answer is
> proabably not, at least for now. The .elc format for compiled functions
> has a single entry for "each" symbol in its constant vector, and it
> would be quite an exercise to augment that with symbols-with-position.
>
> Maybe for the future.
Positions in error messages would be a major improvement as well.
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., (continued)
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Eli Zaretskii, 2018/11/25
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Clément Pit-Claudel, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps.,
Gemini Lasswell <=
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Eli Zaretskii, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/26
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Paul Eggert, 2018/11/27
- Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps., Alan Mackenzie, 2018/11/28