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From "Rana Dasgupta" <rdasg...@gmail.com>
Subject Re: [DRLVM][JIT] write barrier broken by new jit opts?
Date Thu, 11 Jan 2007 22:45:53 GMT
It's hard to understand what these very long threads concluded if one has
not been on it all along.

So:
     1. JIT Optimized arraycopy disabled now
     2. When turned on, gc_safe and will use object remembering barrier
     3. Jit=>gc interface will add  gc::does_it_support_object_remembering()
     4. chunk-wise optimized barrier update unnecessary till someone ever
uses a long enough Java array :-)

   ??

On 1/11/07, Mikhail Fursov <mike.fursov@gmail.com> wrote:
>
> On 1/11/07, Weldon Washburn <weldonwjw@gmail.com> wrote:
> >
> > Actually unless there is some compelling real app data it might make
> sense
> > to hold off attempting any "chunk" optimization.  I think Robin posted
> > some
> > numbers indicating gc latency for a big array copy is probably no big
> deal
> > right now.  Also, adding optimizations that don't help workloads we need
> > to
> > focus on can clutter the code, make debugging harder and reduce
> > reliability.
> >
>
> Yes, I also think so. If memory copying becomes too long it can indicate
> that there is some swapping activity. If this kernel operation is done
> with
> higher priority then normal program execution we have a delay for the
> whole
> system, regardless of number of CPUs. At least I see such a behaviour
> every
> day when my antivirus program run it's scans :)
>
> --
> Mikhail Fursov
>
>

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