ARM11 MPCore: Adding nop to __delay() doubles the BogoMIPS/lpj

Leif Lindholm leif.lindholm at arm.com
Fri Jan 29 10:17:59 EST 2010


> -----Original Message-----
> From: Uwe Kleine-König [mailto:u.kleine-koenig at pengutronix.de]
> Sent: 29 January 2010 14:54

> > But as Catalin says, this makes no functional difference, even though
> > it might look "more impressive" :)
>
> With a bigger number of loops_per_seconds the maximal period that can
> be delayed for is shorter and the granularity is better, no?

I concur that this aspect of my comment was technically incorrect - but if
your code was depending on either of those, surely that would be a problem
in itself?

The minimum time would be questionable anyway, as loops_per_second is an
average, and the branch predictor is fairly likely to miss on the first time
through the loop unless your code uses a lot of delays.
 
/
	Leif






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