From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] virtio: Use ioeventfd for virtqueue notify Date: Sun, 03 Oct 2010 20:18:49 -0500 Message-ID: <4CA92B79.2030805@linux.vnet.ibm.com> References: <1285855312-11739-1-git-send-email-stefanha@linux.vnet.ibm.com> <4CA862A7.2080302@redhat.com> <20101003135138.GA19775@redhat.com> <4CA89185.6070302@redhat.com> <20101003142828.GB19775@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Stefan Hajnoczi , qemu-devel@nongnu.org, kvm@vger.kernel.org, Anthony Liguori , Khoa Huynh , sri@linux.vnet.ibm.com, Steve Dobbelstein To: "Michael S. Tsirkin" Return-path: Received: from e36.co.us.ibm.com ([32.97.110.154]:33936 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750939Ab0JDBTR (ORCPT ); Sun, 3 Oct 2010 21:19:17 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e36.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id o941FB17024201 for ; Sun, 3 Oct 2010 19:15:11 -0600 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o941JGTD100614 for ; Sun, 3 Oct 2010 19:19:16 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o941JFCM010444 for ; Sun, 3 Oct 2010 19:19:16 -0600 In-Reply-To: <20101003142828.GB19775@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/03/2010 09:28 AM, Michael S. Tsirkin wrote: > >> This is using eventfd as well. >> > Sorry, I meant irqfd. > I've tried using irqfd in userspace. It hurts performance quite a bit compared to doing an ioctl so I would suspect this too. A last_used_idx or similar mechanism should help performance quite a bit on top of ioeventfd too. Regards, Anthony Liguori >> -- >> error compiling committee.c: too many arguments to function >>