From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Diestelhorst Subject: Re: Scheduling Date: Tue, 26 Jul 2005 23:43:33 +0100 Message-ID: <42E6BC95.2050004@cl.cam.ac.uk> References: <9588F47251E5BE4A80A34030C4A34314060C0E@ausx3mpc107.aus.amer.dell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9588F47251E5BE4A80A34030C4A34314060C0E@ausx3mpc107.aus.amer.dell.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: David_Wolinsky@Dell.com Cc: m+Ian.Pratt@cl.cam.ac.uk, xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org >I am now changing my scheduling and have noticed some different results, >perhaps you could help me in my studies.... > >I am running CPU intensive VMs and am trying to find out at what >scheduling they'll run the best (since the simulation being run over a >long duration, short periods and slices are not important). I have 8 >VMs so my first few tests were running in periods of 1, 2, and 10 >seconds, divided among the 8 domUs... > > >So I typed >Xm sedf (1,8) 1,2,10e9 125,250,1250e6 0 0 0 >(ie, xm sedf 1 1000000000 125000000 0 0 0) > >In this case, I excluded scheduling for dom0... > >Could you please help me refine my scheduling. > > > Sure. Actually I have not thought of such long periods and slices and in fact there are parts in the code that limit the slice and period lengths to roughly 4 seconds (due to arithmetic overflow), as I guessed that those long periods would be quite exotic. In fact I think you might be better of to use the scheduler in extra-time mode, that means you don't guarantee time to the domains, but rather split the remaining (i.e. when all realtime domains have finished) time into pieces of various sizes. I guess this might be more appropriate to you, I assume that your long running simulation is not a real-time application? So you might just try to do xm sedf (1,8) 0 0 0 1 w With w specifying a weight for the domain. This works intuitively, so a domain with weight 4 gets twice the amount of CPU time as one with weight 2, which gets 2/5 of one with weight 5. I hope that this suits your needs, if not, let me know and I'll change some of the arithmetic code. BTW: What did actually happen when you used the above command? Stephan >-----Original Message----- >From: Ian Pratt [mailto:m+Ian.Pratt@cl.cam.ac.uk] >Sent: Monday, July 25, 2005 11:50 AM >To: Wolinsky, David; xen-devel@lists.xensource.com >Cc: ian.pratt@cl.cam.ac.uk >Subject: RE: [Xen-devel] Scheduling > > > > >>Added sched=rrobin to my kernel and started xen Ran xm rrobin, unknown >> >> > > > >>command Ran xm help rrobin, unkown command >> >> > >sched=rrobin is not in unstable anymore. > >The default is the SEDF scheduler, but you can still set sched=bvt > >As I recall, there is some documentation on SEDF in tools/misc > >We should file a bug that using a scheduler op on a non existent >scheduler does bad things. > >Ian > > > >>So round robin is throw out >> >>So I tried the default bvt... >>Without appending it to my kernel, I ran... xm bvt_ctxallow 1 - >>Error: Internal server error >> >>With it appended to my kernel, I run.. >>xm bvt_ctxallow 1 - Computer hard crashes >> >>Any suggestions? >> >>Thanks, >>David >> >> >> >> > >_______________________________________________ >Xen-devel mailing list >Xen-devel@lists.xensource.com >http://lists.xensource.com/xen-devel > >