From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: Scalable Event Channel ABI design (draft A) Date: Tue, 5 Feb 2013 18:57:58 +0000 Message-ID: <51115636.6080907@citrix.com> References: <51111BCA.3010207@citrix.com> <1360077399.7477.148.camel@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: George Dunlap Cc: Keir Fraser , Wei Liu , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 05/02/13 18:05, George Dunlap wrote: > On Tue, Feb 5, 2013 at 3:16 PM, Wei Liu > wrote: > > > Since the ABI needs to be changed to support more event channels > anyway, > > it seems an ideal point to revisit the design. > > > > Right. I do care about better design and good implementation. Can we > build a prototype of this design? We are less than two months away from > 4.3 feature freeze, and the event channel scalability is planned for > that release, which means we need to be hurried. :-) Two months doesn't seem possible even if I could work on this full time. > I think the general consensus is that scaling event channels is pretty > important -- probably important enough to slip the release a bit if > necessary. (Although it would certainly be better not to.) What to do here is a non-trivial decision. Possible options include: 1. Merge the 3-level ABI for 4.3. Work on the FIFO-based ABI in parallel, aiming to get this in for 4.4. This means maintaining 3 event channel ABIs in Xen. 2. Slip the 4.3 release for 2-3 months and merge the FIFO-based ABI in. 3. Status quo. Defer extending the event channel ABI to 4.4. The preferable option may be to: 4. Get the 3-level ABI to a mergable state. In parallel develop a prototype of the FIFO-based ABI. When the prototype is ready or the 4.3 freeze is here, evaluate it and make a decision then. David