jessie smart
2005-Feb-02 20:23 UTC
[Xen-devel] Performance issuses with Splash2 applications on XEN
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. Jessie jessiesmart354@yahoo.com --------------------------------- Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard.
Ian Pratt
2005-Feb-02 22:29 UTC
RE: [Xen-devel] Performance issuses with Splash2 applications on XEN
Is this using SMP guests from the unstable tree? If so, there''s some serious scheduler issues which are currently being worked on -- its certainly not ready for serious benchmarking (though this might be useful application for us to use for tuning purposes). How many CPUs has the machine you''re running on? How many virtual CPUS does the guest have? Ian> -----Original Message----- > From: xen-devel-admin@lists.sourceforge.net > [mailto:xen-devel-admin@lists.sourceforge.net] On Behalf Of > jessie smart > Sent: 02 February 2005 20:23 > To: xen-devel@lists.sourceforge.net > Subject: [Xen-devel] Performance issuses with Splash2 > applications on XEN > > 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. > > > > Jessie > > jessiesmart354@yahoo.com > > ________________________________ > > Do you Yahoo!? > Read only the mail you want - Yahoo! Mail SpamGuard > <http://us.rd.yahoo.com/mail_us/taglines/spamguard/*http://promotions.yahoo.com/new_mail/static/protection.html> .>------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
jessie smart
2005-Feb-08 01:56 UTC
RE: [Xen-devel] Performance issuses with Splash2 applications on XEN
sorry it took so long for my response....... I am not using the unstable XEN release - I am using XEN 2.0.1 <xen-2.0.1-src.tgz> installed on Fedora Core 3 using "make world" so that it downloads and builds it own kernel. domU (1GB RAM) is booted from a file-backed VBD on a local HDD (I have tested this on a LVM-backed VBD over NFS and see no significant differences). The splash applications that I am using, use the lpthread library. So when I refer to running an application with multiple processors, I am referring to multiple threads <this is how they call it>. The splash applications use a LOT of synchronization objects during their operation (e.g., mutex and conditional variables). Other than that, they simply allocate memory and do a lot of mathematical computations (I.e., floating point). Could the pthread library operations (I.e., pthread synchronization objects) be the cause of the performance hit within domain? Hardware: Tyan s2882 Motherboard Dual 2.0 Ghz AMD Opteron 2GB of RAM Broadcom GB NIC Jessie Smart jessiesmart354@yahoo.com <mailto:jessiesmart354@yahoo.com> Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk> wrote: Is this using SMP guests from the unstable tree? If so, there''s some serious scheduler issues which are currently being worked on -- its certainly not ready for serious benchmarking (though this might be useful application for us to use for tuning purposes). How many CPUs has the machine you''re running on? How many virtual CPUS does the guest have? Ian> -----Original Message----- > From: xen-devel-admin@lists.sourceforge.net > [mailto:xen-devel-admin@lists.sourceforge.net] On Behalf Of > jessie smart > Sent: 02 February 2005 20:23 > To: xen-devel@lists.sourceforge.net > Subject: [Xen-devel] Performance issuses with Splash2 > applications on XEN > > 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. > > > > Jessie > > jessiesmart354@yahoo.com > > ________________________________ > > Do you Yahoo!? > Read only the mail you want - Yahoo! Mail SpamGuard > motions.yahoo.com/new_mail/static/protection.html> . >__________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Mark A. Williamson
2005-Feb-08 02:06 UTC
Re: [Xen-devel] Performance issuses with Splash2 applications on XEN
> domU (1GB RAM) is booted from a file-backed VBD on a local HDD (I have > tested this on a LVM-backed VBD over NFS and see no significant > differences).I wouldn''t recommend exporting filesystems that require high performance over NFS either. Is there any reason not to export the LVM volume directly? i.e. disk = [ ''phy:/path/to/lvm/volume,sda1,w''] This is the preferred configuration for doing serious amounts of IO, since either loop files or NFS will add a load of overhead. Cheers, Mark> > The splash applications that I am using, use the lpthread library. So when > I refer to running an application with multiple processors, I am referring > to multiple threads <this is how they call it>. > > The splash applications use a LOT of synchronization objects during their > operation (e.g., mutex and conditional variables). Other than that, they > simply allocate memory and do a lot of mathematical computations (I.e., > floating point). > > Could the pthread library operations (I.e., pthread synchronization > objects) be the cause of the performance hit within domain? > > > > Hardware: > > Tyan s2882 Motherboard > > Dual 2.0 Ghz AMD Opteron > > 2GB of RAM > > Broadcom GB NIC > > > > > > > > Jessie Smart > > jessiesmart354@yahoo.com <mailto:jessiesmart354@yahoo.com> > > > Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk> wrote: > Is this using SMP guests from the unstable tree? If so, there''s some > serious scheduler issues which are currently being worked on -- its > certainly not ready for serious benchmarking (though this might be > useful application for us to use for tuning purposes). > > How many CPUs has the machine you''re running on? How many virtual CPUS > does the guest have? > > Ian > > > -----Original Message----- > > From: xen-devel-admin@lists.sourceforge.net > > [mailto:xen-devel-admin@lists.sourceforge.net] On Behalf Of > > jessie smart > > Sent: 02 February 2005 20:23 > > To: xen-devel@lists.sourceforge.net > > Subject: [Xen-devel] Performance issuses with Splash2 > > applications on XEN > > > > 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. > > > > > > > > Jessie > > > > jessiesmart354@yahoo.com > > > > ________________________________ > > > > Do you Yahoo!? > > Read only the mail you want - Yahoo! Mail SpamGuard > > motions.yahoo.com/new_mail/static/protection.html> . > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel