Re: [discuss] [PATCH 4/4 TRY#3] optimize and simplifyget_cycles_sync()

From: Joerg Roedel
Date: Mon Mar 12 2007 - 09:47:20 EST


On Mon, Mar 12, 2007 at 02:29:43PM +0100, Michael Matz wrote:
> Hi Joerg,
>
> On Mon, 12 Mar 2007, Joerg Roedel wrote:
>
> > > >+#define RDTSCP ".byte 0x0f, 0x01, 0xf9"
> > > >+ alternative_io_two("cpuid\nrdtsc",
> > > >+ "rdtsc", X86_FEATURE_SYNC_RDTSC,
> > > >+ ".byte 0x0f, 0x01, 0xf9", X86_FEATURE_RDTSCP,
> > > >
> > >
> > > why not use the RDTSCP macro here?
> >
> > Does this macro exist?
>
> Look carefully at your patch again, or at least the four quoted lines
> above. You've added it yourself, in exactly the form you'd need in the
> alternative_io_two() call :-)

Hmmkay, thanks for opening my eyes :-)
I considered defining this macro while writing this patch, but decided
against this because the X86_FEATURE_RDTSCP on the same line should
documenting the opcode sufficiently. I just forgot to remove that
#define :)

Thanks again,
Joerg

--
Joerg Roedel
Operating System Research Center
AMD Saxony LLC & Co. KG


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