Re: [PATCH 2/7] Simple Performance Counters: x86_64 support

[Christoph Lameter]

On Wed, 1 Aug 2007, Andi Kleen wrote:

> Christoph Lameter <clameter@xxxxxxx> writes:
> 
> > Export cycles_to_ns (after renaming the cycles_2_ns to cycles_to_ns to be
> > conforming to other arches).
> 
> This function is broken in some cases (e.g Opteron with powernow or
> AMD dual core or older Intel systems) and going away.  The TSCs tick
> with different frequencies on different CPU there. In general i would
> recommend to only report cycles.

But then the numbers are not comparable across systems.

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