Re: Grow heap aggressively during music interpretation (issue 561390043 by address@hidden)

[Han-Wen Nienhuys]

On Tue, Feb 4, 2020 at 7:50 PM <address@hidden> wrote:

> On 2020/02/02 22:33:50, hanwenn wrote:
> > For testing, use
> >
> > https://github.com/hanwen/lilypond/tree/guile22-experiment
>
> So I ran this with the large example and I see
> GC Warning: Failed to expand heap by 30635458560 bytes
> a few times (that's 30 GB, my laptop only has 8 GB!!) and finally
> warning: g_spawn_sync failed (0): gs: Failed to fork (Cannot allocate
> memory)
> Maybe exponential growth is not the best choice here? At least my system
> can't handle this score anymore.
>
> Also most of the 'speedup' by this patch seems to come from segments
> _after_ music interpretation (only 10% improvement in music
> interpretation, but around 2x for the total time). I think the later
> parts just benefit from the enormous heap because GC doesn't need to run
> at all? But that's not really the idea of this patch, is it?
>
>
In part, it actually is. If you have a lot of RAM, you should use it
instead of trying to waste CPU cycles recycling it.

do you have a pointer to the score for testing?

Can you do some timings with different values for GC_MAXIMUM_HEAP_SIZE , eg.

 GC_MAXIMUM_HEAP_SIZE=100M

Also, it would be interesting to GC_PRINT_STATS=1 and see how much time is
spent in GC, and how much a typical GC runs reclaim across the process.

--
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen