[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC V6 0/11] Paravirtualized ticketlocks
On 04/01/2012 04:48 PM, Raghavendra K T wrote: >>> I have patch something like below in mind to try: >>> >>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >>> index d3b98b1..5127668 100644 >>> --- a/virt/kvm/kvm_main.c >>> +++ b/virt/kvm/kvm_main.c >>> @@ -1608,15 +1608,18 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me) >>> * else and called schedule in __vcpu_run. Hopefully that >>> * VCPU is holding the lock that we need and will release it. >>> * We approximate round-robin by starting at the last boosted >>> VCPU. >>> + * Priority is given to vcpu that are unhalted. >>> */ >>> - for (pass = 0; pass< 2&& !yielded; pass++) { >>> + for (pass = 0; pass< 3&& !yielded; pass++) { >>> kvm_for_each_vcpu(i, vcpu, kvm) { >>> struct task_struct *task = NULL; >>> struct pid *pid; >>> - if (!pass&& i< last_boosted_vcpu) { >>> + if (!pass&& !vcpu->pv_unhalted) >>> + continue; >>> + else if (pass == 1&& i< last_boosted_vcpu) { >>> i = last_boosted_vcpu; >>> continue; >>> - } else if (pass&& i> last_boosted_vcpu) >>> + } else if (pass == 2&& i> last_boosted_vcpu) >>> break; >>> if (vcpu == me) >>> continue; >>> >> >> Actually I think this is unneeded. The loops tries to find vcpus that >> are runnable but not running (vcpu_active(vcpu->wq)), and halted vcpus >> don't match this condition. >> > > > I almost agree. But at corner of my thought, > > Suppose there are 8 vcpus runnable out of which 4 of them are kicked > but not running, making yield_to those 4 vcpus would result in better > lock progress. no? That's what the code does. > I still have little problem getting PLE setup, here (instead > rebasing patches). > Once I get PLE to get that running, and numbers prove no improvement, > I will drop this idea. > I'm interested in how PLE does vs. your patches, both with PLE enabled and disabled. -- error compiling committee.c: too many arguments to function _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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