From: "Gerd Möllmann" <gerd.moellmann@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: yantar92@posteo.net, pipcet@protonmail.com,
emacs-devel@gnu.org, eller.helmut@gmail.com
Subject: Re: MPS: User GC customizations
Date: Thu, 04 Jul 2024 16:30:06 +0200 [thread overview]
Message-ID: <m2bk3dz0up.fsf@pro2.fritz.box> (raw)
In-Reply-To: <86sewp8djd.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 04 Jul 2024 16:58:14 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>> Cc: Pip Cet <pipcet@protonmail.com>, Eli Zaretskii <eliz@gnu.org>,
>> emacs-devel@gnu.org, eller.helmut@gmail.com
>> Date: Thu, 04 Jul 2024 14:51:16 +0200
>>
>> >> igc-step-interval is a variable defined in ‘C source code’.
>> >>
>> >> Its value is 0.1
>> >>
>> >> How much time is MPS allowed to spend in GC when Emacs is idle.
>> >> The value is in seconds, and should be a non-negative number. It can
>> >> be either an integer or a float. The default value is 0 which means .
>> >> don’t do something when idle. Negative values and values that are not numbers
>> >> are handled as if they were the default value.
>> >>
>> >> It's for interactive use.
>> > [...]
>> What this variable does is give MPS notice that the client is currently
>> idle and it might be a good time to do some work.
>
> Is that really what this variable does? My reading of the
> documentation is that it tells MPS how soon to stop GC which it
> started when Emacs was idle. IOW, it's not about _triggering_ GC,
> it's about _ending_ it. And the reason, AFAIU, is to avoid making
> Emacs responses slow because MPS started GC when it detected that
> Emacs is idle.
I'm taking my view from this;:
2.4.6 Using idle time for collection
------------------------------------
Some types of program have “idle time” in which they are waiting for an
external event such as user input or network activity. The MPS provides
a function, *note mps_arena_step(): 19c, for making use of idle time to
make memory management progress.
...
The name interval I've taken from
-- C Function: *note mps_bool_t: 129. mps_arena_step (mps_arena_t
arena, double interval, double multiplier)
‘interval’ is the time, in seconds, the MPS is permitted to take.
It must not be negative, but may be ‘0.0’.
Alas, it doesn't promise to always obey interval:
The MPS makes every effort to
return from this function within ‘interval’ seconds, but cannot
guarantee to do so, as it may need to call your own scanning code.
It uses ‘multiplier’ to decide whether to commence long-duration
operations that consume CPU (such as a full collection): it will
only start such an operation if it is expected to be completed
within ‘multiplier * interval’ seconds.
(Haven't found out yet to prevent full collections with a message "client
predicts plenty of idle time" or some such yet. Please see the comment
in igc.c where mps_arena_step is called.)
next prev parent reply other threads:[~2024-07-04 14:30 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-01 9:26 MPS: Crash when switching to buffer Ihor Radchenko
2024-07-01 12:04 ` Eli Zaretskii
2024-07-01 12:13 ` Ihor Radchenko
2024-07-01 12:46 ` Eli Zaretskii
2024-07-01 14:14 ` Pip Cet
2024-07-01 14:42 ` Gerd Möllmann
2024-07-02 0:22 ` Pip Cet
2024-07-02 4:04 ` Gerd Möllmann
2024-07-02 11:40 ` Ihor Radchenko
2024-07-04 10:31 ` Ihor Radchenko
2024-07-04 11:48 ` Gerd Möllmann
2024-07-04 12:02 ` MPS: User GC customizations (was: MPS: Crash when switching to buffer) Ihor Radchenko
2024-07-04 12:51 ` MPS: User GC customizations Gerd Möllmann
2024-07-04 13:20 ` Ihor Radchenko
2024-07-04 14:45 ` Gerd Möllmann
2024-07-04 15:12 ` Pip Cet
2024-07-04 16:07 ` Gerd Möllmann
2024-07-04 16:38 ` Ihor Radchenko
2024-07-04 17:02 ` Gerd Möllmann
2024-07-04 17:53 ` Eli Zaretskii
2024-07-04 18:18 ` Gerd Möllmann
2024-07-04 18:28 ` Ihor Radchenko
2024-07-04 18:32 ` Pip Cet
2024-07-04 18:43 ` Gerd Möllmann
2024-07-04 18:39 ` Eli Zaretskii
2024-07-04 18:48 ` Ihor Radchenko
2024-07-04 13:58 ` Eli Zaretskii
2024-07-04 14:30 ` Gerd Möllmann [this message]
2024-07-04 15:43 ` Eli Zaretskii
2024-07-04 15:48 ` Eli Zaretskii
2024-07-04 15:52 ` Pip Cet
2024-07-04 16:04 ` Eli Zaretskii
2024-07-04 17:01 ` Gerd Möllmann
2024-07-04 18:03 ` Eli Zaretskii
2024-07-04 18:28 ` Gerd Möllmann
2024-07-04 18:43 ` Eli Zaretskii
2024-07-04 19:09 ` Gerd Möllmann
2024-07-04 19:12 ` Eli Zaretskii
2024-07-04 16:38 ` Pip Cet
2024-07-04 17:06 ` Gerd Möllmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m2bk3dz0up.fsf@pro2.fritz.box \
--to=gerd.moellmann@gmail.com \
--cc=eliz@gnu.org \
--cc=eller.helmut@gmail.com \
--cc=emacs-devel@gnu.org \
--cc=pipcet@protonmail.com \
--cc=yantar92@posteo.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.