Messages in this thread | | | From | "Zhang, Xiantao" <> | Date | Mon, 19 Apr 2010 09:32:12 +0800 | Subject | RE: VM performance issue in KVM guests. |
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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? Gang-scheduling maybe the ideal solution to solve the issue, and has to change host's scheduler a lot to implement it, and it maybe hard to be upstream. So can we figure out an easy way(maybe not best) for this ? Xiantao
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