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From Huming Wu <>
Subject Re: Cassandra performance
Date Thu, 20 Aug 2009 18:05:34 GMT
On Wed, Aug 19, 2009 at 5:45 PM, Michael Greene<> wrote:
> What Jonathan said.  Also, if you have the ability to switch your profiler
> between wall mode and CPU mode, I would recommend it to give you a better
> overall picture of what is going on.  If your profiler can switch between
> 'sampling' and 'tracing' modes that would also be useful.
> I'm not sure if that picture and the profiling description is intended to
> explain the need for incremental GC, but I don't understand it.  What
> difference in memory growth are you seeing?  I'm not sure I can explain that
> based on the GC docs I've read (although I'll be the first to admit I have a
> relatively limited understanding of how it works)

Right. I am probably looking at the wrong place (the waiting time is
counted as cpu usage in the report). I'll try to check out the
profiler to see there is such switch and get a real picture on where
the CPU cycle is spent. On the incremental GC it is not related to the
CPU profiling, I was just responding to your suggestion of removing
that from JVM setting...


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