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From: Eduardo Habkost <ehabkost@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH v2 1/2] kvm: support -realtime cpu-pm=on|off
Date: Wed, 13 Jun 2018 17:35:52 -0300	[thread overview]
Message-ID: <20180613203552.GO7451@localhost.localdomain> (raw)
In-Reply-To: <20180612184616.90838-2-mst@redhat.com>

On Tue, Jun 12, 2018 at 09:47:11PM +0300, Michael S. Tsirkin wrote:
> With this flag, kvm allows guest to control host CPU power state.  This
> increases latency for other processes using same host CPU in an
> unpredictable way, but if decreases idle entry/exit times for the
> running VCPU.
> 
> Follow-up patches will expose this capability to guest
> (using mwait leaf).
> 
> Based on a patch by Wanpeng Li <kernellwp@gmail.com> .
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

The interface makes sense to me, but:

> +extern bool enable_cpu_pm;

Why do we need a global variable if initialization code can call
qemu_opt_get_bool() directly?

-- 
Eduardo

WARNING: multiple messages have this Message-ID (diff)
From: Eduardo Habkost <ehabkost@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Richard Henderson <rth@twiddle.net>,
	kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH v2 1/2] kvm: support -realtime cpu-pm=on|off
Date: Wed, 13 Jun 2018 17:35:52 -0300	[thread overview]
Message-ID: <20180613203552.GO7451@localhost.localdomain> (raw)
In-Reply-To: <20180612184616.90838-2-mst@redhat.com>

On Tue, Jun 12, 2018 at 09:47:11PM +0300, Michael S. Tsirkin wrote:
> With this flag, kvm allows guest to control host CPU power state.  This
> increases latency for other processes using same host CPU in an
> unpredictable way, but if decreases idle entry/exit times for the
> running VCPU.
> 
> Follow-up patches will expose this capability to guest
> (using mwait leaf).
> 
> Based on a patch by Wanpeng Li <kernellwp@gmail.com> .
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

The interface makes sense to me, but:

> +extern bool enable_cpu_pm;

Why do we need a global variable if initialization code can call
qemu_opt_get_bool() directly?

-- 
Eduardo

  reply	other threads:[~2018-06-13 20:35 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-12 18:47 [PATCH v2 0/2] kvm: x86 CPU power management Michael S. Tsirkin
2018-06-12 18:47 ` [Qemu-devel] " Michael S. Tsirkin
2018-06-12 18:47 ` [PATCH v2 1/2] kvm: support -realtime cpu-pm=on|off Michael S. Tsirkin
2018-06-12 18:47   ` [Qemu-devel] " Michael S. Tsirkin
2018-06-13 20:35   ` Eduardo Habkost [this message]
2018-06-13 20:35     ` Eduardo Habkost
2018-06-13 21:00   ` Eduardo Habkost
2018-06-13 21:00     ` [Qemu-devel] " Eduardo Habkost
2018-06-13 21:53     ` Michael S. Tsirkin
2018-06-13 21:53       ` [Qemu-devel] " Michael S. Tsirkin
2018-06-12 18:47 ` [PATCH v2 2/2] i386/cpu: make -cpu host support monitor/mwait Michael S. Tsirkin
2018-06-12 18:47   ` [Qemu-devel] " Michael S. Tsirkin
2018-06-13 21:24   ` Eduardo Habkost
2018-06-13 21:24     ` [Qemu-devel] " Eduardo Habkost
2018-06-12 19:18 ` [PATCH v2 0/2] kvm: x86 CPU power management no-reply
2018-06-12 19:18   ` [Qemu-devel] " no-reply
2018-06-12 20:29   ` Michael S. Tsirkin
2018-06-12 20:29     ` [Qemu-devel] " Michael S. Tsirkin
2018-06-13 22:34 ` Marcelo Tosatti
2018-06-13 22:34   ` [Qemu-devel] " Marcelo Tosatti
2018-06-13 23:37   ` Michael S. Tsirkin
2018-06-13 23:37     ` [Qemu-devel] " Michael S. Tsirkin
2018-06-15 18:32     ` Marcelo Tosatti
2018-06-15 18:32       ` [Qemu-devel] " Marcelo Tosatti
2018-06-15 21:53       ` Michael S. Tsirkin
2018-06-15 21:53         ` [Qemu-devel] " Michael S. Tsirkin
2018-06-14  8:18 ` Daniel P. Berrangé
2018-06-14  8:18   ` [Qemu-devel] " Daniel P. Berrangé
2018-06-14 15:40   ` Paolo Bonzini
2018-06-14 15:40     ` [Qemu-devel] " Paolo Bonzini
2018-06-14 15:44     ` Daniel P. Berrangé
2018-06-14 15:44       ` [Qemu-devel] " Daniel P. Berrangé
2018-06-14 20:32       ` Paolo Bonzini
2018-06-14 20:32         ` [Qemu-devel] " Paolo Bonzini
2018-06-15 14:15         ` Michael S. Tsirkin
2018-06-15 14:15           ` [Qemu-devel] " Michael S. Tsirkin
2018-06-14 16:53     ` Eduardo Habkost
2018-06-14 16:53       ` [Qemu-devel] " Eduardo Habkost
2018-06-14 21:21       ` Paolo Bonzini
2018-06-14 21:21         ` [Qemu-devel] " Paolo Bonzini
2018-06-15 13:52     ` Michael S. Tsirkin
2018-06-15 13:52       ` [Qemu-devel] " Michael S. Tsirkin
2018-06-22 13:06   ` Kashyap Chamarthy
2018-06-22 13:06     ` [Qemu-devel] " Kashyap Chamarthy
2018-06-22 19:18     ` Michael S. Tsirkin
2018-06-22 19:18       ` [Qemu-devel] " Michael S. Tsirkin

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