[PATCH] powerpc: Instrument Hypervisor Calls
kravetz at us.ibm.com
Tue Aug 15 12:32:24 EST 2006
On Tue, Aug 15, 2006 at 11:03:19AM +1000, Stephen Rothwell wrote:
> On Mon, 14 Aug 2006 16:21:44 -0700 Mike Kravetz <kravetz at us.ibm.com> wrote:
> > +#define HCALL_INST_POSTCALL \
> > + /* get time and PURR snapshots after hcall */ \
> > + mftb r7; /* timebase after */ \
> > +BEGIN_FTR_SECTION; \
> > + mfspr r8,SPRN_PURR; /* PURR after */ \
> > +END_FTR_SECTION_IFSET(CPU_FTR_PURR); \
> > + \
> > + /* calculate time and PURR deltas for call */ \
> > + ld r5,STK_PARM(r5)(r1); /* timebase before */ \
> > + subf r5,r5,r7; \
> > + ld r6,STK_PARM(r6)(r1); /* PURR before */ \
> > + subf r6,r6,r8; \
> But here, if we have no PURR we produce random numbers. Maybe you should
> reuse the TB value so the values reported may make some sense.
My intention was to detect the presence of PURR in the display (debugfs)
code. If there is no PURR, then no PURR values are displayed. My thought
is that it doesn't matter what values are in the field if we don't display
Unfortunately, I left that bit of code out of the patch.
How does that sound? Suppose I can also put all the 'calculate PURR delta'
code in the FTR_SECTION to save a few cycles.
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