Thread (49 messages) 49 messages, 8 authors, 2012-01-25

Re: [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests

From: Srivatsa Vaddagiri <hidden>
Date: 2012-01-16 14:20:23
Also in: kvm, xen-devel

* Alexander Graf [off-list ref] [2012-01-16 04:57:45]:
Speaking of which - have you benchmarked performance degradation of pv ticket locks on bare metal?
You mean, run kernel on bare metal with CONFIG_PARAVIRT_SPINLOCKS
enabled and compare how it performs with CONFIG_PARAVIRT_SPINLOCKS disabled for 
some workload(s)?

In some sense, the 1x overcommitcase results posted does measure the overhead
of (pv-)spinlocks no? We don't see any overhead in that case for atleast
kernbench ..
Result for Non PLE machine :
============================
[snip]
Kernbench:
               BASE                    BASE+patch
               %improvement
               mean (sd)               mean (sd)
Scenario A:
case 1x:	 164.233 (16.5506)	 163.584 (15.4598	0.39517
[snip]
Result for PLE machine:
======================
[snip]
Kernbench:
               BASE                    BASE+patch
               %improvement
               mean (sd)               mean (sd)
Scenario A:
case 1x:	 161.263 (56.518)        159.635 (40.5621)	1.00953
- vatsa
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