From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Liu Subject: Re: [PATCH] xen: blkif.h: document linux xen-block multi-page ring implementation Date: Fri, 15 May 2015 18:39:21 +0800 Message-ID: <5555CCD9.5040305@oracle.com> References: <1431428329-6497-1-git-send-email-bob.liu@oracle.com> <5555C1A9.3060106@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5555C1A9.3060106@citrix.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: David Vrabel Cc: justing@spectralogic.com, roger.pau@citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 05/15/2015 05:51 PM, David Vrabel wrote: > 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. > After take a closer look I think we can fully reuse the current protocol which only uses 'ring-page-order' and 'max-ring-page-order'. And leave 'max-ring-pages' and 'num-ring-pages' to DEPRECATED. In conclusion, the blkif.h don't need to be modified and I'll update Linux implementation to use 'ring-page-order' and 'max-ring-page-order' too. What do you think? Thank you! Regards, -Bob