I am using Debian lenny in Dom0. Disk is a two disk md raid1. DomUs have physical lvm. It seems no matter how I assign the affinity in the DomUs:- top on Dom0 shows cpu0 is "clogged up" with typically 0%id 80%wa yet cores 1-3 are 99.7%id. eg: top - 09:20:07 up 11 days, 10:05, 2 users, load average: 0.28, 0.07, 0.06 Tasks: 117 total, 1 running, 116 sleeping, 0 stopped, 0 zombie Cpu0 : 0.3%us, 7.0%sy, 0.0%ni, 6.7%id, 86.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 0.0%us, 0.3%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu3 : 0.0%us, 0.0%sy, 0.0%ni, 98.0%id, 2.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3442688k total, 2419176k used, 1023512k free, 837112k buffers Swap: 39061944k total, 152k used, 39061792k free, 1189380k cached Here is the configuration: Name ID VCPU CPU State Time(s) CPU Affinity Domain-0 0 0 1 -b- 11836.7 any cpu Domain-0 0 1 3 -b- 1326.2 any cpu Domain-0 0 2 2 r-- 2943.1 any cpu Domain-0 0 3 0 -b- 3384.9 any cpu debian 20 0 2 -b- 34.7 1-3 edubuntu 18 0 3 -b- 19.6 1-3 gos 17 0 3 -b- 19.6 1-3 ltsp 15 0 2 -b- 14.4 1-3 Is it possible to spread the load (particularly io) in Dom0 over the 4 cores? Thanks, Berni PS: As an aside I have used tasksel to move the backup job in Dom0 onto core 3 - that does seem to load up cpu0 and 3 more evenly. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Jun 3, 2009 at 3:27 PM, Berni Elbourn <berni@elbournb.fsnet.co.uk> wrote:> I am using Debian lenny in Dom0. Disk is a two disk md raid1. DomUs have > physical lvm. > > It seems no matter how I assign the affinity in the DomUs:- top on Dom0 > shows cpu0 is "clogged up" with typically 0%id 80%wa yet cores 1-3 are > 99.7%id. eg:Most likely you''re I/O bound. Try: - iostat -x 3, see which disk/block device are busy - xm top. Should show you which dom uses most I/O (works for PV guest or HVM with PV drivers) -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Fajar A. Nugraha wrote:> On Wed, Jun 3, 2009 at 3:27 PM, Berni Elbourn > <berni@elbournb.fsnet.co.uk> wrote: >> I am using Debian lenny in Dom0. Disk is a two disk md raid1. DomUs have >> physical lvm. >> >> It seems no matter how I assign the affinity in the DomUs:- top on Dom0 >> shows cpu0 is "clogged up" with typically 0%id 80%wa yet cores 1-3 are >> 99.7%id. eg: > > Most likely you''re I/O bound. Try: > - iostat -x 3, see which disk/block device are busy > - xm top. Should show you which dom uses most I/O (works for PV guest > or HVM with PV drivers) >Hi Fajar, Yes yes the load is caused by using stress in one of the domu using -hdd parameter but it also has -cpu. No matter the cpu configuration it seems most of the load goes on the first core. I am somewhat curious if and how the workload can be spread about more evenly on the cores? Berni _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wed, Jun 3, 2009 at 5:32 PM, Berni Elbourn <berni@elbournb.fsnet.co.uk> wrote:> Fajar A. Nugraha wrote: >> Most likely you''re I/O bound. Try: >> - iostat -x 3, see which disk/block device are busy >> - xm top. Should show you which dom uses most I/O (works for PV guest >> or HVM with PV drivers) >> > > Hi Fajar, Yes yes the load is caused by using stress in one of the domu > using -hdd parameter but it also has -cpu.Is it? from what you wrote the most on dom0 is disk.> > No matter the cpu configuration it seems most of the load goes on the first > core.AFAIK you can''t spread disk I/O load to serveral CPUs. Because that''s not the root cause of the problem. You can : - add more disk, to increase total available I/O throughput - limit disk usage. If it''s domU disk you probably want to put domU''s storage on LVM and use something like dm-ioband : http://people.valinux.co.jp/~ryov/dm-ioband/ -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users