get_cyclecount(9) deprecation

Andriy Gapon avg at freebsd.org
Fri Mar 18 15:51:43 UTC 2011


on 18/03/2011 15:56 Kostik Belousov said the following:
> On Fri, Mar 18, 2011 at 05:26:53PM +1100, Bruce Evans wrote:
> ...
>> - set cputicker() has some design bugs.  It assumes that the tick frequency
>>   is the same across all CPUs, but the TSC is per-CPU.  I have an old SMP
>>   system with CPUs of different frequency that can demonstrate bugs from
>>   this.
> We definitely do not support configurations with different models of
> CPUs in SMP, this is what Simmetric is about. Different as in frequency
> or stepping.

Are there any fundamental reasons for us to not support that configuration in
situations where hardware and BIOS (in x86 case) happen to support it?

I am personally more interested in non-uniform topologies like one package having
two cores and another having four.

-- 
Andriy Gapon


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