Re: xenpm and scheduler

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Apr 12, 2016 at 05:04:04PM +0000, tutu sky wrote:
> Thanks Konrad. I will do :)
> Yeah, I believe so. as i can see that there is not any bios settings for power management in there (vmware).  I hope you be the correct party which i want to ask this question: there is a tutorial here in this page:
> 1) http://xenserver.org/partners/developing-products-for-xenserver/19-dev-help/138-xs-dev-perf-turbo.html
> 
> which i know as a quick guide for establishing xenpm. my Q is that, are this page and this two page of xen.wiki below enough for establishing xenpm and make it work totally?
> 
> 2) http://wiki.xenproject.org/wiki/Xenpm_command
> 3) http://wiki.xenproject.org/wiki/Xen_power_management
> 
>  if yes, there is a problem, when i compiled xen from source, there is not any xensource folder in /opt folder in dom0 to follow the instructions in (1) address. i did all those instructions in dom0 config file instead.

Xen source != XenServer.


> 
> if these guides are not enough in your point of view too, i think (just as a suggestion), xenpm needs more documentation, in order to clarify it's activation and usage progress. it remains a silent area in this giant project although is quiet usable.
>

If you run 'xenpm' by itself it gives you the options.

Patches to make an manpage for xenpm are always warmly welcome!
> thanks and regards.
> 
> ________________________________________
> From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Sent: Tuesday, April 12, 2016 1:41 PM
> To: tutu sky
> Cc: Dario Faggioli; Meng Xu; Xen-devel@lists.xen.org
> Subject: Re: [Xen-devel] xenpm and scheduler
> 
> On Tue, Apr 12, 2016 at 11:50:42AM +0000, tutu sky wrote:
> > Thanks Dario,
> > Yeah, I do like playing with xenpm and try understanding relationship between this and scheduler. but i established a xen environment on vmware, but xenpm does not work correctly and even for 'cpufreq', it is silent at all! so it does not let me try to play with :(. I asked this problem before in the user and devel lists both,  but no body answered me. how can i track the problem, from who (I know that power management is out of your maintenance scope)?? (may xenpm have the same problem on a real platform (again) instead of vmware?)
> > thanks a lot.
> 
> You will have to.
> 
> I don't believe VMWare exposes C and P states to guests so therefore
> there is no power freqeuency in play.
> 
> > regards.
> > ________________________________________
> > From: Dario Faggioli <dario.faggioli@citrix.com>
> > Sent: Tuesday, April 12, 2016 8:10 AM
> > To: tutu sky; Meng Xu
> > Cc: Xen-devel@lists.xen.org
> > Subject: Re: [Xen-devel] xenpm and scheduler
> >
> > On Tue, 2016-04-12 at 03:52 +0000, tutu sky wrote:
> > > Thanks Xu. I will do as desired about cross messaging.
> > >
> > > i need it because i exactly want to know that which part of the
> > > scheduler's corde (credit), takes effect from this feature. because
> > > it is important to me knowing that where would be trade off between
> > > idle state and doing load balancing, while cpuidle feature is
> > > activated. in other side it's important again for me that what will
> > > happen for 'cap; and 'weight' decreasing in a case that one core's
> > > frequency is lower than another one in the same socket (actually when
> > > cpufreq feature is enable).
> > >
> > Currently, there is no interaction between the scheduler and the power
> > management and frequency scaling layers.
> >
> > > Am i clear enough? can you give me an answer or maybe some lines of
> > > schedule.c or sched_credit.c's code which i can track them to notice
> > > the effect of xenpm on scheduler part of the view?
> > >
> > If you're saying that, for instance, the CPUs changing frequency can or
> > should affect some aspects of the scheduling algorithms (like credits
> > burning rate in Credit1 and Credit2, and budget burning rate in RTDS),
> > that is an interesting point which may indeed make sense, or at least
> > would deserve more investigation.
> >
> > But again, right now, there's no line of code to read to understand the
> > relationship, as there's no relationship at all.
> >
> > If you want to experiment on playing with xenpm, and seeing what effect
> > it has on scheduling, that will be very welcome. :-)
> >
> > Regards,
> > Dario
> > --
> > <<This happens because I choose it to happen!>> (Raistlin Majere)
> > -----------------------------------------------------------------
> > Dario Faggioli, Ph.D, http://about.me/dario.faggioli
> > Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel

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