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SubjectRe: [RFC][PATCH 10/14] x86: generic aperf/mperf code.
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On Fri, 2009-09-04 at 10:22 -0400, Dave Jones wrote:
> On Fri, Sep 04, 2009 at 11:27:19AM +0200, Peter Zijlstra wrote:
> > On Fri, 2009-09-04 at 11:25 +0200, Peter Zijlstra wrote:
> > > On Fri, 2009-09-04 at 11:19 +0200, Thomas Renninger wrote:
> > > > You still use struct perf_pair split/hi/lo members in #ifdef __i386__
> > > > case which you deleted above.
> > >
> > > > > shift_count = fls(h);
> > > > >
> > > > > - cur.aperf.whole >>= shift_count;
> > > > > - cur.mperf.whole >>= shift_count;
> > > > > + cur.aperf >>= shift_count;
> > > > > + cur.mperf >>= shift_count;
> > > > > }
> > > > >
> > > > > if (((unsigned long)(-1) / 100) < cur.aperf.split.lo) {
> > > > Same here, possibly still elsewhere.
> > > > Is this only x86_64 compile tested?
> > >
> > > Of course, who still has 32bit only hardware anyway ;-)
> > >
> > > Will fix, thanks for spotting that.
> >
> > Hrmm, on that, does it really make sense to maintain the i386 code path?
> >
> > How frequently is that code called and what i386 only chips support
> > aperf/mperf, atom?
>
> any 64-bit cpu that supports it can have a 32bit kernel installed on it.
> (and a significant number of users actually do this).

1) we really should be pushing those people to run 64bit kernels

[ I'm still hoping distros will start shipping 64bit kernels and have
the bootloader pick the 64bit one when the hardware supports lm ]

2) those cpus aren't real bad at 64bit divisions :-)



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