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From Huming Wu <huming...@gmail.com>
Subject Re: Cassandra performance
Date Thu, 20 Aug 2009 00:32:18 GMT
On Tue, Aug 18, 2009 at 12:02 PM, Michael
Greene<michael.greene@gmail.com> wrote:
> According to the HBase guys and confirmed by
> http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html#icms,
> on an 8-core machine you are not going to want to enable
> -XX:+CMSIncrementalMode -- it is for 1 or 2 core machines that are
> using the CMS GC.  This should affect your latency numbers positively,
> but I wouldn't see it changing the CPU usage much.

Looks I do need to use the incremental GC though otherwise the memory
growth is very fast... On the get_slice CPU, I tried the profiling (on
single node and low load 1 get_slice call per second) and it looks
org.apache.thrift.transport.TIOStreamTransport.read sucks up all CPU.
Here is the snapshot
http://farm3.static.flickr.com/2595/3838562412_8ffb42ea8c_o.png
(sounds an issue in thrift). Any idea?

Thanks,
Huming

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