lkml.org 
[lkml]   [2019]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available
On Thu, Aug 01, 2019 at 06:54:49PM +0200, Paolo Bonzini wrote:
> On 01/08/19 18:51, Rafael J. Wysocki wrote:
> > On 8/1/2019 9:06 AM, Wanpeng Li wrote:
> >> From: Wanpeng Li <wanpengli@tencent.com>
> >>
> >> The downside of guest side polling is that polling is performed even
> >> with other runnable tasks in the host. However, even if poll in kvm
> >> can aware whether or not other runnable tasks in the same pCPU, it
> >> can still incur extra overhead in over-subscribe scenario. Now we can
> >> just enable guest polling when dedicated pCPUs are available.
> >>
> >> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >> Cc: Paolo Bonzini <pbonzini@redhat.com>
> >> Cc: Radim Krčmář <rkrcmar@redhat.com>
> >> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> >> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> >
> > Paolo, Marcelo, any comments?
>
> Yes, it's a good idea.
>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Paolo

I think KVM_HINTS_REALTIME is being abused somewhat.
It has no clear meaning and used in different locations
for different purposes.

For example, i think that using pv queued spinlocks and
haltpoll is a desired scenario, which the patch below disallows.

Wanpeng Li, currently the driver does not autoload. So polling in
the guest has to be enabled manually. Isnt that sufficient?


\
 
 \ /
  Last update: 2019-08-03 22:25    [W:0.098 / U:35.312 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site