Messages in this thread | | | From | Nikunj A Dadhania <> | Subject | Re: [RFC PATCH 0/4] Gang scheduling in CFS | Date | Tue, 27 Dec 2011 16:13:26 +0530 |
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On Tue, 27 Dec 2011 12:34:34 +0200, Avi Kivity <avi@redhat.com> wrote: > On 12/27/2011 12:10 PM, Nikunj A Dadhania wrote: > > On Tue, 27 Dec 2011 11:51:46 +0200, Avi Kivity <avi@redhat.com> wrote: > > > On 12/27/2011 11:44 AM, Nikunj A Dadhania wrote: > > > > > > I am seeing a drop of ~44% when setting yield_on_hlt = 0 > > > > > > > > > > > > > > > > A drop of 44% of what? > > > > > > > > > records/sec > > > > > > > > Ebizzy - 2VM running in parallel, both having gang scheduling enabled. > > > > > > > > yield_on_hlt=1 yield_on_hlt=0 > > > > EbzyRecords/sec 41955.50 23285.00 -44 > > > > > > > > > > > > > > Interesting, are you overcommitting vcpus? > > > > > Yes(1:2). On a 8cpu machine, have 2VMs running, which is 8vcpus each. > > Ah, yield_on_hlt=0 isn't any good with overcommit. The vcpu stays > scheduled when idle, so other vcpus don't get to use its cpu time. > This is similar to booting the guest with idle=poll kernel parameter?
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