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Re: [PATCH] rs6000: Add a builtin to read the time base register on PowerPC
On Wed, Aug 29, 2012 at 01:56:05PM -0400, Hans-Peter Nilsson wrote:
> On Wed, 29 Aug 2012, Segher Boessenkool wrote:
> > On some systems the timebase runs at a rather low frequency, say 20MHz.
> > This test will spuriously fail there. Waste a million CPU cycles before
> > reading TB the second time?
>
> Waste said million cycles portably by calling sched_yield()?
> (Available only on POSIX systems. :)
Well only for a test environment. You don't want to call sched_yield in the
normal case, since the apps that do this many millions of times need this to be
as a fast as possible.
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Michael Meissner, IBM
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