From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60620) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yiemg-00043a-4V for qemu-devel@nongnu.org; Thu, 16 Apr 2015 04:04:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yiemc-00069w-U3 for qemu-devel@nongnu.org; Thu, 16 Apr 2015 04:04:26 -0400 Received: from mail-wi0-x231.google.com ([2a00:1450:400c:c05::231]:35992) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yiemc-00069i-M4 for qemu-devel@nongnu.org; Thu, 16 Apr 2015 04:04:22 -0400 Received: by wizk4 with SMTP id k4so184346523wiz.1 for ; Thu, 16 Apr 2015 01:04:22 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <552F6D02.4080309@redhat.com> Date: Thu, 16 Apr 2015 10:04:18 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <552E1EB4.3030805@clodo.ru> <20150416012735.GB21291@ad.nay.redhat.com> In-Reply-To: <20150416012735.GB21291@ad.nay.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] virtio-blk and virtio-scsi performance comparison List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , Konstantin Krotov Cc: qemu-devel@nongnu.org On 16/04/2015 03:27, Fam Zheng wrote: > > virtio-scsi, on the other hand, provides more features and means to be more > scalable (you won't need to painfully mess with pci bridges to attach 1000 > disks). > > Anyway, we are working on improving virtio-scsi performance, although it's > theoretically impossible to make it faster or even equally fast. > > Regarding your test, I think with current code base, it generally performs > better if you use io=native. Have you compared that? Also, make sure you're using the deadline scheduler in both host and guest. Paolo