Messages in this thread | | | Date | Sat, 31 Mar 2012 09:39:15 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH RFC V6 0/11] Paravirtualized ticketlocks |
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* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> [2012-03-31 09:37:45]:
> The issue is with ticketlocks though. VCPUs could go into a spin w/o > a lock being held by anybody. Say VCPUs 1-99 try to grab a lock in > that order (on a host with one cpu). VCPU1 wins (after VCPU0 releases it) > and releases the lock. VCPU1 is next eligible to take the lock. If
Sorry I meant to say "VCPU2 is next eligible ..."
> that is not scheduled early enough by host, then remaining vcpus would keep > spinning (even though lock is technically not held by anybody) w/o making > forward progress. > > In that situation, what we really need is for the guest to hint to host > scheduler to schedule VCPU1 early (via yield_to or something similar).
s/VCPU1/VCPU2 ..
- vatsa
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