From: Gleb Natapov <gleb@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Avi Kivity <avi@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"mtosatti@redhat.com" <mtosatti@redhat.com>
Subject: Re: [PATCH 0/8] use jump labels to streamline common APIC configuration
Date: Tue, 14 Aug 2012 17:08:06 +0300 [thread overview]
Message-ID: <20120814140805.GO11194@redhat.com> (raw)
In-Reply-To: <502A5B42.2040102@siemens.com>
On Tue, Aug 14, 2012 at 04:05:54PM +0200, Jan Kiszka wrote:
> On 2012-08-14 16:04, Avi Kivity wrote:
> > On 08/14/2012 05:00 PM, Jan Kiszka wrote:
> >
> >>>> The host can prevent this by leaving disabling the guest pmu. But
> >>>> disabling jump labels for real-time kernels may be acceptable too. We
> >>>> can probably to it at run time by forcing the slow path at all times.
> >>> Yes, it is possible to add module option that will force slow path if
> >>> needed.
> >>
> >> Should I write a patch or will you? Having host-side stop_machine due to
> >> such common guest operations is indeed a no-go for RT.
> >>
> >
> > Note that an additional patch is needed for perf, otherwise the guest
> > (or a user, but that's less of a concern for realtime) can easily invoke
> > stop_machine by configuring and unconfiguring its pmu.
>
> Hmm, can't the PMU be blocked by taking away some CPU features?
>
It can.
--
Gleb.
next prev parent reply other threads:[~2012-08-14 14:08 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-05 12:58 [PATCH 0/8] use jump labels to streamline common APIC configuration Gleb Natapov
2012-08-05 12:58 ` [PATCH 1/8] KVM: clean up kvm_(set|get)_apic_base Gleb Natapov
2012-08-05 12:58 ` [PATCH 2/8] KVM: use kvm_lapic_set_base() to change apic_base Gleb Natapov
2012-08-05 12:58 ` [PATCH 3/8] KVM: mark apic enabled on start up Gleb Natapov
2012-08-05 14:14 ` Avi Kivity
2012-08-05 14:17 ` Gleb Natapov
2012-08-05 14:39 ` Avi Kivity
2012-08-05 14:43 ` Gleb Natapov
2012-08-05 12:58 ` [PATCH 4/8] Export jump_label_rate_limit() Gleb Natapov
2012-08-05 14:16 ` Avi Kivity
2012-08-06 12:37 ` Jason Baron
2012-08-05 12:58 ` [PATCH 5/8] KVM: use jump label to optimize checking for HW enabled APIC in APIC_BASE MSR Gleb Natapov
2012-08-05 14:35 ` Avi Kivity
2012-08-05 14:42 ` Gleb Natapov
2012-08-05 14:48 ` Avi Kivity
2012-08-05 14:55 ` Gleb Natapov
2012-08-05 12:58 ` [PATCH 6/8] KVM: use jump label to optimize checking for SW enabled apic in spurious interrupt register Gleb Natapov
2012-08-05 12:58 ` [PATCH 7/8] KVM: use jump label to optimize checking for in kernel local apic presence Gleb Natapov
2012-08-05 12:58 ` [PATCH 8/8] KVM: inline kvm_apic_present() and kvm_lapic_enabled() Gleb Natapov
2012-08-05 13:33 ` [PATCH 0/8] use jump labels to streamline common APIC configuration Avi Kivity
2012-08-05 13:35 ` Gleb Natapov
2012-08-05 13:42 ` Avi Kivity
2012-08-05 13:48 ` Gleb Natapov
2012-08-05 14:00 ` Avi Kivity
2012-08-05 14:03 ` Gleb Natapov
2012-08-14 14:00 ` Jan Kiszka
2012-08-14 14:03 ` Gleb Natapov
2012-08-14 14:20 ` Jan Kiszka
2012-08-14 14:37 ` Gleb Natapov
2012-08-14 14:58 ` Jan Kiszka
2012-08-14 16:21 ` Avi Kivity
2012-08-14 16:38 ` Jan Kiszka
2012-08-14 17:00 ` Avi Kivity
2012-08-14 17:16 ` Jan Kiszka
2012-08-14 14:04 ` Avi Kivity
2012-08-14 14:05 ` Jan Kiszka
2012-08-14 14:08 ` Gleb Natapov [this message]
2012-08-14 14:07 ` Gleb Natapov
2012-08-14 14:13 ` Jan Kiszka
2012-08-14 14:44 ` Gleb Natapov
2012-08-14 15:09 ` Jan Kiszka
2012-08-05 19:30 ` Eric Northup
2012-08-06 8:35 ` Avi Kivity
2012-08-06 8:52 ` Gleb Natapov
2012-08-06 13:23 ` Avi Kivity
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