From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Andrew D. Ball" Subject: Re: PV drivers for HVM guests Date: Thu, 05 Oct 2006 10:59:55 -0400 Message-ID: <45251DEB.1070708@us.ibm.com> References: <4523C843.E57C.0030.0@novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4523C843.E57C.0030.0@novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ky Srinivasan Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Agreed. What I meant is that it would be nice if the device model were modified to have better performance for things like OS/2, where writing paravirtual drivers would be less emphasized. Peace. Andrew Ky Srinivasan wrote: > Andrew, > > The I/O performance of HVM guests with PV drivers is SIGNIFICANTLY better than what we get without PV drivers. I will post the patches after some additional testing and code cleanup. > > Regards, > > K. Y > > >>>>On Tue, Oct 3, 2006 at 6:19 PM, in message > > <1159913996.27206.37.camel@localhost>, "Andrew D. Ball" > wrote: > >>Interesting! Ideally, there would be better performance in the base HVM >>device model. I think I know of some people that are working hard on >>that. >> >>I'm curious to see what you've done for (1) and (2). >> >>Peace. >>Andrew >> >>On Tue, 2006- 10- 03 at 16:31 - 0400, Ky Srinivasan wrote: >> >>>I am trying to build PV drivers for SLES9 HVM guests. SLES 9 is based on the >> >>2.6.5 kernel. Since the PV driver code is really designed for the latest >>kernel release, I have had many issues/problems in building the PV drivers >>for older Linux OS targets - I have only been looking at the issues with 2.6.5 >>kernel base and I suspect the problem will be even worse if one were to look >>at older Linux kernels. This is unfortunate since PV drivers are so critical >>for HVM guests and there is considerable interest in supporting legacy Linux >>environments as HVM guests. The problems I have had to deal with can be >>broadly classified into: >> >>>a) Compiler related issues >>>b) Missing functionality in the legacy kernel - this includes features as >> >>well as changed data structures >> >>>c) Implementation differences of a given feature >>> >>>These differences can be dealt with in a couple of different ways: >>>1) Modify the code in the PV drivers under appropriate compilation switches >> >>to deal with the differences in the base kernels. >> >>>2) Introduce a compatibility component that bridges the gap between the >> >>current PV code and a given Linux target and leave much of the PV driver >>code untouched. >> >>>I have implemented both these schemes for the sles9 kernel and would like to >> >>get your input on your preference. I personally like option 2. Going forward, >>the evolution of PV drivers needs to be constrained by the required support >>for legacy Linux environments. >> >>>Regards, >>> >>>K. Y. Srinivasan >>> >>> >>> >>> >>> >>>_______________________________________________ >>>Xen- devel mailing list >>>Xen- devel@lists.xensource.com >>>http://lists.xensource.com/xen- devel >> >> >>_______________________________________________ >>Xen- devel mailing list >>Xen- devel@lists.xensource.com >>http://lists.xensource.com/xen- devel > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel >