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<TITLE>RE: [xep-support] multi threaded access issue ?</TITLE>
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<P><FONT SIZE=2>Thanks David, but I don't believe Garbage collection is the issue. When I disable the hyper-threading on the HT box I get an increase in performance given the same number of threads (2). As when the Hyper-Threading was enabled. Further, our second test machine, the 2 CPU, box is an extremley powerful machine, both CPUs are Dual core Xeon, in excess of 3.0 Ghz each. I have 2 Gigs of Ram on this box and the heap size is set to 1 Gig. During memory analysis I have seen that my memeory usage "peaked" at apx 198MB, no where close to the 1 Gig Limit I have set. </FONT></P>
<P><FONT SIZE=2>Thanks again</FONT>
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<P><FONT SIZE=2>Rob</FONT>
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<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: owner-xep-support@renderx.com [<A HREF="mailto:owner-xep-support@renderx.com">mailto:owner-xep-support@renderx.com</A>] On Behalf Of David Tolpin</FONT>
<BR><FONT SIZE=2>Sent: Monday, February 06, 2006 11:52 AM</FONT>
<BR><FONT SIZE=2>To: xep-support@renderx.com</FONT>
<BR><FONT SIZE=2>Subject: Re: [xep-support] multi threaded access issue ?</FONT>
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<P><FONT SIZE=2>> Any ideas as to why this is happening ?</FONT>
<BR><FONT SIZE=2>></FONT>
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<P><FONT SIZE=2>When you run multiple threads on the same machine with the same memory limit, you get much more memory use. Garbage collector in JVM is 'stop the world' by default. This means that with increased memory churning you spend more time in all the threads waiting for the garbage collector to complete (which has low priority, by the way).</FONT></P>
<P><FONT SIZE=2>You need also four times more memory and/or ParallelGC enable to benefit from multiple threads.</FONT>
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<P><FONT SIZE=2>David Tolpin</FONT>
<BR><FONT SIZE=2> </FONT>
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