issues with hwpmc and athlon XP

[Adrian Chadd]

On 17/03/2008, Joseph Koshy <jkoshy at freebsd.org> wrote:


>  It so happens that the Athlon XP machine I purchased had one of those
>  BIOSes that do not enable the local APIC.  So I couldn't get those
>  PMCs to deliver an interrupt and wasn't able to test sampling on this
>  processor.  That was frustrating, especially since Linux 2.4 and later
>  can override the BIOS and use the LAPIC; we can't.

Hm, why can they but we can't?

>  Onto debugging this bug: my first question is: does system sampling
>  (i.e.. pmcstat -S) work OK on this CPU?

It returned results. I don't know how valid the results were. In fact,
I'm still not getting user-space info from pmcstat -P but that
partially may be user error. I'm seeing NMI's which are logged against
a user trapframe but nothing shows up in my profiling output.. it
could be attributing it to the library/libraries instead of the
process.





Adrian

-- 
Adrian Chadd - adrian at freebsd.org