[PATCH 0/3] powerpc: Instrument Hypervisor Calls

Arnd Bergmann arnd at arndb.de
Sun Jul 16 02:42:26 EST 2006

On Saturday 15 July 2006 17:30, Anton Blanchard wrote:
> > What happened to the question whether to use PURR values for also measuring
> > cycles spent executing the hcall as opposed to cycles that passed before
> > the hcall returns. Did that turn out not giving extra information after all
> > or was there a different reason to drop that idea?
> You have to be careful with PURR since it may be context switched
> between partitions.

Not sure I follow you. I would expect the PURR value to be restored after
a context switch, even if we continue on a different physical CPU.

The idea behind monitoring both PURR and timebase is that the difference
between the two tells you how long the partition was suspended during
the hcall.

	Arnd <><

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