Hi everyone, I was just investigating scheduling of VMs on Xen, and so I was logging the following data from inside __enter_scheduler (in xen/common/schedule.c): id: prev->id duration: now - prev->lastschd Now, suppose I have domain0 and another VM (the first created after dom0, thus gets a domain ID of 1) running. And to simplify matters I''m using the round robin scheduler with default params (i.e. 10ms slice). Now I would have expected to see dom0 (id=0) and the lone VM (id=1) scheduled alternately. However, I see a lot of instances where the id as recorded above reports a value of 32767. I''m guessing this is the hypervisor? It''ll be great if someone can shed some light on this -- does the scheduler treat the hypervisor as just another domain? It''ll be great if someone can shed more light on whats going on here. Thanks, Diwaker -- Diwaker Gupta http://resolute.ucsd.edu/diwaker ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
Diwaker Gupta wrote:> However, I see a lot of instances where the id as recorded above > reports a value of 32767. I''m guessing this is the hypervisor? It''ll > be great if someone can shed some light on this -- does the scheduler > treat the hypervisor as just another domain?ID 32767 is the "idle" domain, which runs whenever there''s no runnable domain. Rob ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
On 8 Mar 2005, at 20:13, Rob Gardner wrote:> Diwaker Gupta wrote: >> However, I see a lot of instances where the id as recorded above >> reports a value of 32767. I''m guessing this is the hypervisor? It''ll >> be great if someone can shed some light on this -- does the scheduler >> treat the hypervisor as just another domain? > > ID 32767 is the "idle" domain, which runs whenever there''s no runnable > domain.I think the round-robin scheduler might include the idle domain in the round-robin schedule. It really is very brain-dead -- I expect we will remove it as part of our current scheduler cleanups. -- Keir ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel
> I think the round-robin scheduler might include the idle domain in the > round-robin schedule. It really is very brain-dead -- I expect we will > remove it as part of our current scheduler cleanups.Yes, it schedules everything on the runqueue, including the idle domain - it''s only there as an example of the scheduler API. It used to print "Stupid Round Robin Scheduler" at boot time but I think that got edited out ;-) Cheers, Mark ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xen-devel