From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48398) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QYwvm-0007JV-Nh for qemu-devel@nongnu.org; Tue, 21 Jun 2011 05:07:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QYwvl-0001bG-Fp for qemu-devel@nongnu.org; Tue, 21 Jun 2011 05:07:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4080) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QYwvk-0001b8-QQ for qemu-devel@nongnu.org; Tue, 21 Jun 2011 05:07:33 -0400 Message-ID: <4E005F4E.1060200@redhat.com> Date: Tue, 21 Jun 2011 12:07:26 +0300 From: Avi Kivity MIME-Version: 1.0 References: <1308577094-17551-1-git-send-email-gollub@b1-systems.de> <20110620153825.GH13042@redhat.com> <4DFF6B20.7090107@redhat.com> <201106201826.32975.gollub@b1-systems.de> <4DFF76B1.8020509@redhat.com> <20110621060251.GB491@redhat.com> <4E0051B1.8060801@redhat.com> <20110621084155.GD491@redhat.com> <4E005CBA.3000105@redhat.com> <20110621090348.GE491@redhat.com> In-Reply-To: <20110621090348.GE491@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2] Introduce panic hypercall List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: Daniel Gollub , qemu-devel , kvm@vger.kernel.org On 06/21/2011 12:03 PM, Gleb Natapov wrote:> >> > > >Something like steal time, but for watchdog. But this become complicated fast. > > >Watchdog emulation will have to move into kernel for starter. > > > > Why? You can use a performance counter from userspace. > > > Heh, haven't thought about such way of implementing watchdog device. > But the same question again: what impact on performance constantly running > guest under perf is? Same answer. > Doesn't running guest under perf involve a lot of > NMIs (and hence vmexists)? The NMI rate is proportional to how you program the counter. If you program it to exit every 2 billion cycles, that's what you'll get. -- error compiling committee.c: too many arguments to function