MPS: User GC customizations (was: MPS: Crash when switching to buffer)

[Ihor Radchenko]

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> Hi Ihor. Soemthing completely unrelated, but I think it might be
> interesting to play with if you are running an igc Emacs more often:
>
>   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.

IMHO, this variable makes little sense in isolation. It only makes sense
to postpone GCs when we also have the means to increase the thresholds
when to trigger them. Most of the time, GCs are triggered by
memory-intensive commands. Extra GC on idle would not help those.

For example, my recent measurement of building agendas displayed 30% of
the time spend in GC. (whatever this means in the context of our handling
of SIGPRF)

-- 
Ihor Radchenko // yantar92,
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