lkml.org 
[lkml]   [2012]   [Mar]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH RFC V6 0/11] Paravirtualized ticketlocks
    * 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



    \
     
     \ /
      Last update: 2012-03-31 06:13    [W:1.418 / U:0.024 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site