Re: MPS: User GC customizations

[Ihor Radchenko <yantar92@posteo.net>]

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

> Pip mentioned scan functions, so let's say we set a flag in_scan while
> being in dflt_scan. MPS now calls dflt_scan, in the MPS thread, to do an
> increment of its work. While in dflt_scan we get SIGPROF and land in the
> signal handler in main thread, and the profiler sees in_scan == true.
>
> Q: do we count that as part of GC work that the profiler should report,
> although it happened in the MPS thread? I understood Ihor as saying that
> he doesn't want that.

I think that we should ideally have multiple flags like this:
1. when arena is locked
2. when our dflt_scan code is running
3. when we query MPS synchronously (e.g. memory allocation)
4. when Emacs thread is paused by MPS

Then, we can report statistics for each flag.

I think that it can give us some idea about how different aspects of MPS
affect Emacs responsiveness.

-- 
Ihor Radchenko // yantar92,
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