From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH] xen: blkif.h: document linux xen-block multi-page ring implementation Date: Fri, 15 May 2015 10:51:37 +0100 Message-ID: <5555C1A9.3060106@citrix.com> References: <1431428329-6497-1-git-send-email-bob.liu@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1431428329-6497-1-git-send-email-bob.liu@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Bob Liu , xen-devel@lists.xen.org Cc: justing@spectralogic.com, roger.pau@citrix.com List-Id: xen-devel@lists.xenproject.org On 12/05/15 11:58, Bob Liu wrote: > After commit 1b1586eeeb8c ("xenbus_client: Extend interface to > support multi-page ring"), Linux xenbus driver can support multi-page ring. > > Based on this interface, we got some impressive improvements by using multi-page > ring in xen-block driver. If using 64 pages as the ring, the IOPS increased > about 15 times for the throughput testing. > > The Linux implementation reuses two 'DEPRECATED' nodes('max-ring-pages' and > 'num-ring-pages), so that nothing would be broken. > Also removed the power of 2 limit and updated the default/max value accordingly. You can't drop the power of 2 restriction as there may be frontends that support this old option (from before it was deprecated) and these may not support non-powers of 2. David