Re: [Engine-devel] CPU Pinning @engine

From: "Dor Laor" <dlaor(a)redhat.com&gt; To: "Doron Fediuck" <dfediuck(a)redhat.com&gt; Cc: engine-devel(a)ovirt.org Sent: Monday, May 21, 2012 11:01:58 AM Subject: Re: [Engine-devel] CPU Pinning @engine On 05/21/2012 10:58 AM, Doron Fediuck wrote: > On 21/05/12 01:45, Andrew Cathrow wrote: >> >> >> ----- Original Message ----- >>> From: "Doron Fediuck&quot;&lt;dfediuck(a)redhat.com&gt; >>> 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).

> >> >>> >>>>> 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&quot;&lt;dfediuck(a)redhat.com&gt; >>>>>>> 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 >>> > > _______________________________________________ Engine-devel mailing list Engine-devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel