From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=42356 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PHbYZ-0001k6-2f for qemu-devel@nongnu.org; Sun, 14 Nov 2010 07:19:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PHbYY-00016m-3w for qemu-devel@nongnu.org; Sun, 14 Nov 2010 07:19:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:8854) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PHbYX-00016i-TT for qemu-devel@nongnu.org; Sun, 14 Nov 2010 07:19:38 -0500 Message-ID: <4CDFD3BE.8090702@redhat.com> Date: Sun, 14 Nov 2010 14:19:10 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH 2/3] virtio-pci: Use ioeventfd for virtqueue notify References: <1289483242-6069-1-git-send-email-stefanha@linux.vnet.ibm.com> <1289483242-6069-3-git-send-email-stefanha@linux.vnet.ibm.com> <20101111164518.GA28773@infradead.org> <4CDFBB19.7010702@redhat.com> <4CDFC288.9050800@redhat.com> In-Reply-To: <4CDFC288.9050800@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Christoph Hellwig , "Michael S. Tsirkin" , Stefan Hajnoczi , kvm@vger.kernel.org, qemu-devel@nongnu.org On 11/14/2010 01:05 PM, Avi Kivity wrote: >> I agree, but let's enable virtio-ioeventfd carefully because bad code >> is out there. > > > Sure. Note as long as the thread waiting on ioeventfd doesn't consume > too much cpu, it will awaken quickly and we won't have the > "transaction per timeslice" effect. > > btw, what about virtio-blk with linux-aio? Have you benchmarked that > with and without ioeventfd? > And, what about efficiency? As in bits/cycle? -- error compiling committee.c: too many arguments to function