[lkml]   [2012]   [Mar]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH RFC V6 0/11] Paravirtualized ticketlocks
* Srivatsa Vaddagiri <> [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

 \ /
  Last update: 2012-03-31 06:13    [W:0.139 / U:10.280 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site