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<DIV><FONT size=2 face=Arial>Hyper-threading usually lowers the performance by
5-15% in HPC environment, </FONT></DIV>
<DIV><FONT size=2 face=Arial>you'd better turn it off. </FONT><FONT size=2
face=Arial>HT benefits applications in enterprise environment where
</FONT></DIV>
<DIV><FONT size=2 face=Arial>the CPU usage is about </FONT><FONT size=2
face=Arial>15-25% so that a physical CPU core can handle two </FONT></DIV>
<DIV><FONT size=2 face=Arial>threads effectively in a time-</FONT><FONT size=2
face=Arial>sharing way. </FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Huiqun Zhou</FONT></DIV>
<DIV><FONT size=2 face=Arial>@Earth Sciences, Nanjing University,
China</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=quantumdft@gmail.com href="mailto:quantumdft@gmail.com">vega lew</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pw_forum@pwscf.org
href="mailto:pw_forum@pwscf.org">PWSCF Forum</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, November 27, 2009 1:23
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Pw_forum] Do you think QE could
benefit from the Hyper-ThreadingTech of XEON 5500 series?</DIV>
<DIV><BR></DIV>Dear all,<BR><BR>I got 5 computers with two XEON 5520 and 24G
memory. I find the Hyper-Threading is switched on by default. I wonder if QE
could benefit from Hyper-Threading Tech. of Xeon CPUs?<BR>Should I switch it
off and trigger one process for each core to promote the QE performance?<BR>Or
remain the Hyper-Threading on and trigger two processes for each
core?<BR><BR>best<BR><BR>vega<BR clear=all><BR>--
<BR>==================================================================================<BR>Vega
Lew ( weijia liu)<BR>Graduate student<BR>State Key Laboratory of
Materials-oriented Chemical Engineering<BR>College of Chemistry and Chemical
Engineering<BR>Nanjing University of Technology, 210009, Nanjing, Jiangsu,
China<BR>******************************************************************************************************************<BR>Email:
<A href="mailto:vegalew@gmail.com">vegalew@gmail.com</A><BR>Office: Room A705,
Technical Innovation Building, Xinmofan Road 5#, Nanjing, Jiangsu, China
<BR>******************************************************************************************************************
<BR>
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