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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] XEN Proposal
That was grouping domains to directly share scheduling credits, rather than grouping to share physical resources. -- Keir On 10/12/2008 13:21, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote: > I remember seeing some post before about domain group scheduler. > Not sure about its progress now, and maybe you can check that > thread to see anything useful? > > Thanks, > Kevin > >> From:Juergen Gross >> Sent: Wednesday, December 10, 2008 9:10 PM >> >> Hi, >> >> Currently the XEN credit scheduler has its pitfalls in >> supporting weights of >> domains together with cpu pinning (see the threads >> http://lists.xensource.com/archives/html/xen-devel/2007-02/msg0 >> 0006.html >> http://lists.xensource.com/archives/html/xen-devel/2006-10/msg0 >> 0365.html >> http://lists.xensource.com/archives/html/xen-devel/2007-07/msg0 >> 0303.html >> which include a rejected patch). >> >> We are facing this problem, too. We tried the above patch, but >> it didn't solve >> our problem completely, so we decided to start a new solution. >> >> Our basic requirement is to limit a set of domains to a set of >> physical cpus >> while specifying the scheduling weight for each domain. The >> general (and in my >> opinion best) solution would be the introduction of a "pool" >> concept in XEN. >> >> Each physical cpu is dedicated to exactly one pool. At start >> of XEN this is >> pool0. A domain is member of a single pool (dom0 will always >> be member of >> pool0), there may be several domains in one pool. Scheduling >> does not cross >> pool boundaries, so the weight of a domain is only related to >> the weight of >> the other domains in the same pool. So it is possible to have >> an own scheduler >> for each pool. >> >> What changes would be needed? >> - The hypervisor must be pool-aware. It needs information >> about the pool >> configuration (cpu mask, scheduler) and the pool membership >> of a domain. >> The scheduler must restrict itself to its own pool only. >> - There must be an interface to set and query the pool configuration. >> - At domain creation the domain must be added to a pool. >> - libxc must be expanded to support the new interfaces. >> - xend and the xm command must support pools, defaulting to >> pool0 if no pool >> is specified >> >> The xm commands could look like this: >> xm pool-create pool1 ncpu=4 # create a pool with 4 cpus >> xm pool-create pool2 cpu=1,3,5 # create a pool with >> 3 dedicated cpus >> xm pool-list # show pools: >> pool cpus sched domains >> pool0 0,2,4 credit 0 >> pool1 6-9 credit 1,7 >> pool2 1,3,5 credit 2,3 >> xm pool-modify pool1 ncpu=3 # set new number of cpus >> xm pool-modify pool1 cpu=6,7,9 # modify cpu-pinning >> xm pool-destroy pool1 # destroy pool >> xm create vm5 pool=pool1 # start domain in pool1 >> >> There is much more potential in this approach: >> - add memory to a pool? Could be interesting for NUMA >> - recent discussions on xen-devel related to scheduling >> (credit scheduler for >> client virtualization) show some demand for further work >> regarding priority >> and/or grouping of domains >> - this might be an interesting approach for migration of >> multiple related >> domains (pool migration) >> - move (or migrate?) a domain to another pool >> - ... >> >> Any comments, suggestions, work already done, ...? >> Otherwise we will be starting our effort soon. >> >> Juergen >> >> -- >> Juergen Gross Principal Developer >> IP SW OS6 Telephone: +49 (0) 89 636 47950 >> Fujitsu Siemens Computers e-mail: >> juergen.gross@xxxxxxxxxxxxxxxxxxx >> Otto-Hahn-Ring 6 Internet: www.fujitsu-siemens.com >> D-81739 Muenchen Company details: >> www.fujitsu-siemens.com/imprint.html >> >> >> >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@xxxxxxxxxxxxxxxxxxx >> http://lists.xensource.com/xen-devel >> > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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