[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Question about support for acpi_cpufreq module in Xen
Does Xen support changes to the processor P-state using acpi_cpufreq module? I have an Intel core2-duo machine with 2 physical CPUs (4 logical CPUs in total) and acpi_cpufreq does not seem to work properly When I run the command cpufreq-info (in dom0), I get the following: > cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006 > Report errors and bugs to linux@xxxxxxxx, please. > analyzing CPU 0: > driver: acpi-cpufreq > CPUs which need to switch frequency at the same time: 0 > hardware limits: 2.00 GHz - 3.00 GHz > available frequency steps: 3.00 GHz, 2.00 GHz > available cpufreq governors: userspace, performance > current policy: frequency should be within 2.00 GHz and 3.00 GHz. > The governor "userspace" may decide which speed to use > within this range. > current CPU frequency is 3.00 GHz. > analyzing CPU 1: > driver: acpi-cpufreq > CPUs which need to switch frequency at the same time: 1 > hardware limits: 2.00 GHz - 3.00 GHz > available frequency steps: 3.00 GHz, 2.00 GHz > available cpufreq governors: userspace, performance > current policy: frequency should be within 2.00 GHz and 3.00 GHz. > The governor "userspace" may decide which speed to use > within this range. > current CPU frequency is 3.00 GHz. > analyzing CPU 2: > no or unknown cpufreq driver is active on this CPU > analyzing CPU 3: > no or unknown cpufreq driver is active on this CPU It seems acpi_cpufreq is not recognizing 2 of my CPUs. I think this problem is somehow related to the fact that if two cores share the same socket they cannot be set to distinct Power states. Xen is reporting that the 4 CPUs are in 4 distinct physical CPUs (siblings=1) when each physical CPU has 2 cores, and this may be confusing acpi_cpufreq. (see the difference in /proc/cpuinfo between Xen and Linux in the attached files). Is this a well known problem? Is there any way to fix this? I thought Xen has been fixed to report the right physical CPU topology but maybe I am wrong. Any help would be greatly appreciated Thanks Renato PS - I am using xen-unstable c/s 17193:f33328217eee Attachment:
cpuinfo_linux Attachment:
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