On Tue, Sep 11, 2012 at 08:52:51AM -0400, Laszlo Hornyak wrote: > > > ----- Original Message ----- > > From: "Dan Kenigsberg" <[email protected]> > > To: "Laszlo Hornyak" <[email protected]> > > Cc: "engine-devel" <[email protected]>, "Omer Frenkel" > > <[email protected]> > > Sent: Tuesday, September 11, 2012 2:34:13 PM > > Subject: Re: [Engine-devel] what does engine with cpuIdle? > > > > On Tue, Sep 11, 2012 at 07:38:11AM -0400, Laszlo Hornyak wrote: > > > > > > ----- Original Message ----- > > > > From: "Dan Kenigsberg" <[email protected]> > > > > To: "Omer Frenkel" <[email protected]> > > > > Cc: "Laszlo Hornyak" <[email protected]>, "engine-devel" > > > > <[email protected]> > > > > Sent: Tuesday, September 11, 2012 9:22:15 AM > > > > Subject: Re: [Engine-devel] what does engine with cpuIdle? > > > > > > > > On Tue, Sep 11, 2012 at 01:55:01AM -0400, Omer Frenkel wrote: > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > From: "Laszlo Hornyak" <[email protected]> > > > > > > To: "engine-devel" <[email protected]> > > > > > > Sent: Monday, September 10, 2012 3:51:59 PM > > > > > > Subject: [Engine-devel] what does engine with cpuIdle? > > > > > > > > > > > > hi, > > > > > > > > > > > > I am trying to change a behavior in vdsm. When you pass 100% > > > > > > load > > > > > > on > > > > > > a VM, it will stop reporting further load and will keep > > > > > > telling > > > > > > 100% > > > > > > until the load drops under 100% again in it's cpuIdle > > > > > > information. > > > > > > This is totally correct if you have only single-cpu VM's, but > > > > > > it > > > > > > is > > > > > > false when you have multiple vcpu's, I think the cpuIdle > > > > > > information > > > > > > should not be on a 0-100 scale, but on a 0-100*vcpus scale. > > > > > > > > > > > > So I submitted this patch to vdsm: > > > > > > http://gerrit.ovirt.org/#/c/7892/2 > > > > > > and Dan pointed out that some functionality may depend on the > > > > > > value > > > > > > in the 0-100 interval. For me it seems it is ignored and the > > > > > > load > > > > > > is > > > > > > calculated only from sysCpu + userCpu. Does anyone build on > > > > > > the > > > > > > cpuIdle value? > > > > > > > > > > > > Thanks, > > > > > > Laszlo > > > > > > > > > > > > > > > > you are right, engine doesn't save cpuIdle for vm, > > > > > so it's not in use in the engine. > > > > > > > > Laszlo, in this case, I think it would be best to drop this bogus > > > > piece > > > > of information. > > > > > > Ok. > > > > > > However, before I abandon this patch: > > > > Why abandon? I've suggested you to keep it, just make it even > > simpler. > > Ok, it is only burocracy, but the new patch will do something > completely different than the original, so it does not seem to make > sense to continue this patch. It is more simple to make another one.
Actually, if the patch has the same intentions, I prefer to keep it as another version - this way it is easier to see if former comments have been addressed. But it's your code and your call. > > > > > > we have a requirement to report cpuSys and cpuUser separately. > > > Afaik > > > in libvirt cpuUser and cpuSys does not include the actual guest > > > time > > > (at least not with KVM), and in this way if we only report cpuSys > > > and > > > cpuUser, the sum does not give the actual load, only a relatively > > > little percentage of it. > > > > I am not sure I understand what you are saying, but afaik, libvirt's > > relatively-new > > http://libvirt.org/html/libvirt-libvirt.html#virDomainGetCPUStats > > reports the cpu time spent by the entire qemu process - in guest and > > host modes. > > It seems like sysCpu + userCpu < cpuTime, therefore something is > missing. I will give it another try, maybe something wrong with my > hosts. I may well be wrong. http://libvirt.org/html/libvirt-libvirt.html#VIR_DOMAIN_CPU_STATS_CPUTIME someone would have to compare your report requirement with what libvirt provides. > > > > > > If we have the cpuIdle information in engine, > > > we can calculate the guest time. Therefore, should I - include the > > > guest time in cpuSys or cpuUser? > > > - add another exported field? > > > > > > And in both case, we will still have to calculate from cpuIdle > > > because > > > libvirt does not tell the guest cpu time :-( > > > > Now I'm completely at loss. Why should we calculate cpuIdle per VM? > > Haven't we agreed that it is useless? > > Well, if libvirt exports the guest time in sysCpu, then we do not have > to. But it seems it does not. Even we should jump throguh hoops to get the data you require, I do not see how cpuIdle is related (or actually, what it means). Dan. _______________________________________________ Engine-devel mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/engine-devel
