Messages in this thread | | | Subject | Re: [PATCH] cpuidle-haltpoll: Enable kvm guest polling when dedicated physical CPUs are available | From | "Rafael J. Wysocki" <> | Date | Thu, 1 Aug 2019 18:51:10 +0200 |
| |
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?
> --- > drivers/cpuidle/cpuidle-haltpoll.c | 3 ++- > drivers/cpuidle/governors/haltpoll.c | 2 +- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c > index 9ac093d..7aee38a 100644 > --- a/drivers/cpuidle/cpuidle-haltpoll.c > +++ b/drivers/cpuidle/cpuidle-haltpoll.c > @@ -53,7 +53,8 @@ static int __init haltpoll_init(void) > > cpuidle_poll_state_init(drv); > > - if (!kvm_para_available()) > + if (!kvm_para_available() || > + !kvm_para_has_hint(KVM_HINTS_REALTIME)) > return 0; > > ret = cpuidle_register(&haltpoll_driver, NULL); > diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c > index 797477b..685c7007 100644 > --- a/drivers/cpuidle/governors/haltpoll.c > +++ b/drivers/cpuidle/governors/haltpoll.c > @@ -141,7 +141,7 @@ static struct cpuidle_governor haltpoll_governor = { > > static int __init init_haltpoll(void) > { > - if (kvm_para_available()) > + if (kvm_para_available() && kvm_para_has_hint(KVM_HINTS_REALTIME)) > return cpuidle_register_governor(&haltpoll_governor); > > return 0;
| |