On mar, 2013-05-21 at 15:28 +0100, Massimo Canonico wrote: > On 05/21/2013 03:06 PM, Dario Faggioli wrote: > > Also, when inspecting the vCPU utilization, do you see the VM vCPU busy > > up to 100% without cap (or with cap set to 100) and, OTOH, up to 50% > > with cap set to 50? > I have monitored the CPU usage with xentop during the experiment and > I got what you said: my application always use the total amonut of CPU > available. > Ok. > > Well, looks like a scheduling issue, or, in any case, one where > > something is interacting with the scheduling. Can you perhaps boot Dom0 > > so that it uses only 2 or 3 cores (or arrange for that later, e.g., with > > cpupools) and pin the vCPU of the VM on the 4th one? > In my experiments, I pin the vCPU of the VM on one core and other cores > are pinned to Dom0. > [root@csitest ~]# xl vcpu-list > Name ID VCPU CPU State Time(s) CPU > Affinity > Domain-0 0 0 0 --- 383.3 0 > Domain-0 0 1 0 -b- 358.1 0 > Domain-0 0 2 0 -b- 224.3 0 > Domain-0 0 3 0 r-- 256.8 0 > rubis-web 1 0 2 -b- 9250.9 2 > > (rubis-web is, of course, the VM where my application run) > > Is this configuration what you meant? > Sort of. However, since (you said) you have 4 cores, what I was thinking was more a situation where you have the 4 Dom0 vCPUs pinned to cores 0-2, and the VM vCPU pinned to core 3. You should be able to achieve that by doing right this: # xl vcpu-pin 0 all 0-2 # xl vcpu-pin rubis-web all 3 Does it make sense? Oh, and also, you have 4 _actual_cores_, right? Or is there any hyperthreading involved? Dario -- <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)