From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34820) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fTCUq-00026t-CF for qemu-devel@nongnu.org; Wed, 13 Jun 2018 16:36:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fTCUn-0006EG-9I for qemu-devel@nongnu.org; Wed, 13 Jun 2018 16:36:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37708) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fTCUn-0006DJ-3B for qemu-devel@nongnu.org; Wed, 13 Jun 2018 16:35:57 -0400 Date: Wed, 13 Jun 2018 17:35:52 -0300 From: Eduardo Habkost Message-ID: <20180613203552.GO7451@localhost.localdomain> References: <20180612184616.90838-1-mst@redhat.com> <20180612184616.90838-2-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180612184616.90838-2-mst@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 1/2] kvm: support -realtime cpu-pm=on|off List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, Paolo Bonzini , Marcelo Tosatti , Richard Henderson , kvm@vger.kernel.org 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 . > > Signed-off-by: Michael S. Tsirkin 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