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[Xen-devel] Performance issuses with Splash2 applications on XEN

  • To: xen-devel@xxxxxxxxxxxxxxxxxxxxx
  • From: jessie smart <jessiesmart354@xxxxxxxxx>
  • Date: Wed, 2 Feb 2005 12:23:04 -0800 (PST)
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I am running one of the applications from the Stanford splash2 application suite ( http://www-flash.stanford.edu/apps/ ) and getting an unexpected (~5x) performance decrease in domU when specifying more than 1 processor in the application.   dom0 seems to handle this fine.


Specificly I am seeing this on the water-nsquared app.  I am not going to give my machine config here (if you need them please ask) just the differences in runtime and the parameters of the app.



all are running single processor & 1GB RAM

(times reported as real/user/system, in seconds)


water-nsquared 64 processors 8000 molecules


baseline (non-xen) 72.20/78.80/0.17

Dom0                   77.76/77.17/0.16

DomU                   357.24/357.04/0.018


water-nsquared 1 processor 8000 molecules


baseline (non-xen) 73.16/72.75/0.15

Dom0                   72.75/72.37/0.02

DomU                   66.07/66.04/0.02



I have disabled the /lib/tls.


I am hoping that someone here with a little more experience with Xen can help me try to explain this.  Any input would be greatly appreciated.




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