On 05/03/2011 01:37 PM, Jan Kiszka wrote:
> > Yes. Unfortunately that is very vendor and model specific. The > architectural PMU is supported, but that is only available on Intel. Is it supposed to have any practical value already? I did not yet find a magic -cpu switch to let Linux detect anything, not to speak of perf or watchdog support.
On the guest side it is supported for the watchdog (arch/x86/kernel/cpu/perfctr-watchdog.c, look for X86_FEATURE_ARCH_PERFMON). It's also mentioned in perf_event_intel.c, but I don't know if it will work without the other PMU features being present.
> > Perhaps we could emulate the architectural PMU on AMD as well, and make > the detection code in the guest vendor agnostic. Since it's based on a > cpuid bit, it should be safe. > We may only make Linux happy this way, no?
I would argue that if a feature is discoverable by a cpuid bit it shouldn't need to be qualified by vendor. No idea how other OSes work this out (or even if they make use of the architectural PMU).
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