Messages in this thread | | | Subject | Re: VM performance issue in KVM guests. | From | Peter Zijlstra <> | Date | Fri, 16 Apr 2010 12:40:36 +0200 |
| |
On Thu, 2010-04-15 at 09:43 -0700, Srivatsa Vaddagiri wrote: > On Thu, Apr 15, 2010 at 03:33:18PM +0200, Peter Zijlstra wrote: > > On Thu, 2010-04-15 at 11:18 +0300, Avi Kivity wrote: > > > > > > Certainly that has even greater potential for Linux guests. Note that > > > we spin on mutexes now, so we need to prevent preemption while the lock > > > owner is running. > > > > either that, or disable spinning on (para) virt kernels. Para virt > > kernels could possibly extend the thing by also checking to see if the > > owner's vcpu is running. > > I suspect we will need a combination of both approaches, given that we will not > be able to avoid preempting guests in their critical section always (too long > critical sections or real-time tasks wanting to preempt). Other idea is to > gang-schedule VCPUs of the same guest as much as possible?
Except gang scheduling is a scalability nightmare waiting to happen. I much prefer this hint thing.
| |