Re: [rfc][patch] 1/2 Additional cpuset features

[Paul Jackson]

> Simon's 2nd patch provides a translation that we need at SGI for perfmon
> support within a cpuset. Without the virtualization some
> means in user space needs to exist to translate a virtual CPU number
> into a physical CPU number.

In my opinion, user space is exactly the right place for this translation.

Those inside SGI can see more detail of this in SGI Incident 903969.

But the jist of the matter is simple.  Just as we (SGI) did with
cpumemsets and perfmon on 2.4 kernels, so should we do with cpusets and
perfmon on 2.6 kernels.  And that is to perform this translation in
perfmon code.  Is it only SGI's dplace that requires the cpuset-relative
numbering?

The kernel-user boundary should stick to a single, system-wide, numbering
of CPUs.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@xxxxxxx> 1.650.933.1373
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