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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] 99% iowait on one core in 8 core processor
Hi, Thank You. Your response makes a lot of sense to me. I will try to move all domU away from cpu0. On 11-Jul-2012, at 7:26 PM, Matthias wrote: > Hi, > > I experianced the same. > > I figured the reason behind this has nothing to do with what (v)cpus > you assign to the domUs. In fact, I think that the real reason is that > all I/O emulation from the domUs (like HDD, Network and Stuff) is all > handled by CPU0 of dom0, even in a multi-core-architecture. > > You can test this with trying something I/O intensive like a hdd > benchmark in the domU and you will see the dom0-cpu0 utilization > rising. > > Using PVHVM or GPLPV-Driver only reduces the amount of utilization but > it is still handled by cpu0 only. Due to that fact i leave cpu0 to my > dom0 alone and only assign the other cpu-cores to the domUs. > > > Note: This is only an assumption I made after seeing my machines > behaviour. If the above isn't true, please correct me. > > > 2012/7/11 Rajesh Kumar <rajesh@xxxxxxxx>: >> Hi All, >> >> We have a xen server and using 8 core processor. >> >> I can see that there is 99% iowait on only core 0. >> >> >> 02:28:49 AM CPU %user %nice %sys %iowait %irq %soft %steal >> %idle intr/s >> 02:28:54 AM all 0.00 0.00 0.00 12.65 0.00 0.02 2.24 >> 85.08 1359.88 >> 02:28:54 AM 0 0.00 0.00 0.00 96.21 0.00 0.20 3.19 >> 0.40 847.11 >> 02:28:54 AM 1 0.00 0.00 0.00 6.41 0.00 0.00 9.42 >> 84.17 219.56 >> 02:28:54 AM 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 100.00 2.59 >> 02:28:54 AM 3 0.00 0.00 0.00 0.00 0.00 0.00 2.12 >> 97.88 76.25 >> 02:28:54 AM 4 0.00 0.00 0.00 0.00 0.00 0.00 1.20 >> 98.80 118.56 >> 02:28:54 AM 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 100.00 3.59 >> 02:28:54 AM 6 0.00 0.00 0.00 0.00 0.00 0.00 2.02 >> 97.98 89.62 >> 02:28:54 AM 7 0.00 0.00 0.00 0.00 0.00 0.00 0.20 >> 99.80 2.59 >> >> 02:28:54 AM CPU %user %nice %sys %iowait %irq %soft %steal >> %idle intr/s >> 02:28:59 AM all 0.00 0.00 0.00 12.48 0.00 0.00 2.78 >> 84.74 1317.43 >> 02:28:59 AM 0 0.00 0.00 0.00 98.80 0.00 0.00 0.80 >> 0.40 885.17 >> 02:28:59 AM 1 0.00 0.00 0.00 0.00 0.00 0.00 11.38 >> 88.62 151.30 >> 02:28:59 AM 2 0.00 0.00 0.00 0.00 0.00 0.00 0.20 >> 99.80 2.81 >> 02:28:59 AM 3 0.00 0.00 0.00 0.00 0.00 0.00 7.21 >> 92.79 94.79 >> 02:28:59 AM 4 0.00 0.00 0.00 0.00 0.00 0.00 2.20 >> 97.80 170.34 >> 02:28:59 AM 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 100.00 4.41 >> 02:28:59 AM 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 100.00 5.81 >> 02:28:59 AM 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 100.00 2.81 >> >> >> I have even tries changing the cpus mapped to the DomU with out no effect. >> >> Name CPU CPU Affinity >> 4pulse 1 1 >> 2music 3 3 >> Domain-0 0 0 >> Domain-0 1 1 >> Domain-0 2 2 >> Domain-0 3 3 >> Domain-0 4 4 >> Domain-0 5 5 >> Domain-0 6 6 >> Domain-0 7 7 >> analshah 6 any cpu >> arunvelayudhan 7 any cpu >> backup 7 any cpu >> crickruns 3 1-3 >> crickruns 2 1-3 >> crickruns 1 1-3 >> crickruns 2 1-3 >> crickruns 1 1-3 >> crickruns 1 1-3 >> dedicatedjv 7 any cpu >> yeluthu 4 3-5 >> yeluthu 3 3-5 >> yeluthu 3 3-5 >> yeluthu 3 3-5 >> yeluthu 3 3-5 >> yeluthu 3 3-5 >> freshnfresh 3 any cpu >> monitoring 7 any cpu >> reporter 6 5-7 >> reporter 7 5-7 >> reporter 6 5-7 >> reporter 6 5-7 >> reporter 7 5-7 >> reporter 7 5-7 >> reporter 5 5-7 >> reporter 7 5-7 >> radio03 7 any cpu >> saampeter 2 1-2 >> saampeter 2 1-2 >> >> >> Thanks, >> Rajesh >> _______________________________________________ >> Xen-users mailing list >> Xen-users@xxxxxxxxxxxxx >> http://lists.xen.org/xen-users _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxx http://lists.xen.org/xen-users
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