Re: [Engine-devel] CPU Pinning @engine

On 21/05/12 11:01, Dor Laor wrote: > On 05/21/2012 10:58 AM, Doron Fediuck wrote: >> On 21/05/12 01:45, Andrew Cathrow wrote: >>> >>> ----- Original Message ----- >>>> From: "Doron Fediuck"<dfediuck(a)redhat.com> >>>> To: dlaor(a)redhat.com >>>> Cc: engine-devel(a)ovirt.org >>>> Sent: Sunday, May 20, 2012 5:49:08 PM >>>> Subject: Re: [Engine-devel] CPU Pinning @engine >>>> >>>> On 20/05/12 21:41, Dor Laor wrote: >>>>> On 05/17/2012 11:15 PM, Doron Fediuck wrote: >>>>>> On 17/05/12 20:28, Ayal Baron wrote: >>>>>>> "Live migration will not be supported for such VM's." >>>>>>> >>>>>>> Migration will work on homogeneous clusters so this should not be >>>>>>> enforced (not limited to VMs which are pinned to host) just give >>>>>>> a warning. >>>>>>> >>>>>> I agree, but if we wish to ping vCPUx to pCPUy in host a, we >>>>>> cannot ensure to have the same in host b, >>>>>> since it may have pCPUy too busy, so performance will degrade. >>>>>> Also, I hope you saw my general comment >>>>> Performance may degrade on any migration to loaded host regardless >>>>> of pinning. >>>>> >>>>> There is not need to forbid migration. Instead, the SLA assurance >>>>> policy should verify the dedicated resources and match the target >>>>> w/ the guarantee and decide according to this. >>>>> >>>> Thanks for the input. >>>> We may start with migration blocked in a configurable manner, so >>>> people who wish migrate to work >>>> will simply set the relevant configuration key. >>>> As for looking for a matched CPU, will add it as p2. >>> We shouldn't block migration >>> If a user wants to not migrate a cpu pinned VM then let them use the non-migratable flag in the UI. >>> >> We're not blocking migration, we're allowing pinning (for now) only for non-migrative VM's. >> For p2 we'll verify destination host has the relevant pinning capacity, which will allow >> pinning for migrative VM's as well. > > IMHO the order should be the opposite - if the user likes to migrate a pinned VM, let him (you can pop some message if you like). I'll check it with UI guys (AFAIK engine UI has no pop-ups). Also, I prefer safe than sorry. So start with a safe working pinning for pinned-to-host VMs, and then push the envelope.

>>>>>> about starting with a humble solution and gradually improving. In >>>>>> this context (auto)numa can help us, >>>>>> so we better do numa than handle migration for basic mode, risking >>>>>> performance issues. >>>>>> >>>>>>> ----- Original Message ----- >>>>>>>> From: "Doron Fediuck"<dfediuck(a)redhat.com> >>>>>>>> To: engine-devel(a)ovirt.org >>>>>>>> Sent: Thursday, May 17, 2012 2:42:46 PM >>>>>>>> Subject: [Engine-devel] CPU Pinning @engine >>>>>>>> >>>>>>>> Hi All, >>>>>>>> Currently the VDSM has a CPU pinning hook. >>>>>>>> We'd like to add better support of it into the engine itself. >>>>>>>> Here's a design draft to cover it: >>>>>>>> http://www.ovirt.org/wiki/Features/Design/cpu-pinning >>>>>>>> >>>>>>>> Please review and comment if needed. >>>>>>>> >>>>>>>> Thanks! >>>>>>>> -- >>>>>>>> >>>>>>>> /d >>>>>>>> >>>>>>>> Never say "OOPS!" always say "Ah, Interesting!" >>>>>>>> _______________________________________________ >>>>>>>> Engine-devel mailing list >>>>>>>> Engine-devel(a)ovirt.org >>>>>>>> http://lists.ovirt.org/mailman/listinfo/engine-devel >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> Engine-devel mailing list >>>>>>> Engine-devel(a)ovirt.org >>>>>>> http://lists.ovirt.org/mailman/listinfo/engine-devel >>>>>> >>>> >>>> -- >>>> >>>> /d >>>> >>>> Never say "OOPS!" always say "Ah, Interesting!" >>>> _______________________________________________ >>>> Engine-devel mailing list >>>> Engine-devel(a)ovirt.org >>>> http://lists.ovirt.org/mailman/listinfo/engine-devel >>>> >>