Messages in this thread | | | Date | Tue, 14 Feb 2012 20:30:06 +0200 | From | Pasi Kärkkäinen <> | Subject | Re: [Xen-devel] [RFC] acpi processor and cpufreq harester - aka pipe all of that up to the hypervisor (v3) |
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On Tue, Feb 14, 2012 at 12:06:46AM -0500, Konrad Rzeszutek Wilk wrote: > > This "harvester" (I am horrible with names, if you have any suggestions please > tell me them) collects the information that the cpufreq drivers and the > ACPI processor code save in the 'struct acpi_processor' and then sends it to > the hypervisor. >
Btw there's a typo in the subject line.. "harester".
I'm not very good with names either: collector? passthru?
> The driver can be either an module or compiled in. In either mode the driver > launches a thread that checks whether an cpufreq driver is registered. If so > it reads all the 'struct acpi_processor' data for all online CPUs and sends > it to hypervisor. The driver also register a CPU hotplug component - so if a new > CPU shows up - it would send the data to the hypervisor for it as well. > > I've tested this with success on a variety of Intel and AMD hardware (need > a patch to the hypervisor to allow the rdmsr to be passed through). The one > caveat is that dom0_max_vcpus inhibits the driver from reading the vCPUs > that are not present in dom0. One solution is to boot without dom0_max_vcpus > and utilize the 'xl vcpu-set' command to offline the vCPUs. Other one that > Nakajima Jun suggested was to hotplug vCPUS in - so bootup dom0 and hotplug > the vCPUs in - but I am running in difficulties on how to do this in the hypervisor. >
When using this driver do you need to pass any options to Xen hypervisor? (cpufreq=something) ?
It might be good to mention something about that in the patch comments.
-- Pasi
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