[ruby-core:87189] Re: [Ruby trunk Feature#14767] [PATCH] gc.c: use monotonic counters for objspace_malloc_increase

пт, 18 мая 2018 г., 11:47 Eric Wong <[e-mail]>:

> Eric Wong <[e-mail]> wrote:
> > OK.  Also, did we ever consider signed type (`ssize_t`) for malloc
> > counters instead?  This may be more useful if we switch to
> > thread-local storage for counters to avoid atomics.
>
> Reverted for now because of regressions in:
>
>             bm_array_sample_100k__6k
>             bm_array_sample_100k___10k
>             bm_array_sample_100k___50k
>
> I think the original unsigned + underflow avoidance code
> prevented us from accounting free() properly, and we were
> triggering GC more as a result.
>
> With this patch, frees are accounted properly so malloc_increase
> grew too slowly...
>

Why triggerring GC less frequently considered as disadvantage?
I think, real aplications will benefit from it.
Why this benchmarks suffers from it?


> Also, I think it would be beneficial to check malloc_increase
> and do a lazy sweep step BEFORE calling malloc, since that should
> improve cache locality in malloc (because they're usually LIFO).
>
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