Re: [PATCH] optimize writer path in time_interpolator_get_counter()

[Christoph Lameter]

On Wed, 3 Aug 2005, Alex Williamson wrote:

> be a reasonable performance vs absolute accuracy trade-off.  What
> happens to your worst case time if you (just for a test) hard code a
> min_delta of something around 20-50?  There could be some kind of

Think about a threaded process that gets time on multiple processors 
and then compares the times. This means that the time value obtained later 
on one thread may indicate a time earlier than that obtained on another 
thread. An essential requirement for time values is that they are 
monotonically increasing. You are changing that basic nature.

> boot/run time tunable to set this min_delta if there's no good way to
> calculate it.  It should be trivial to add something like this to the
> fsys path as well and shouldn't disrupt the nojitter path at all.

I assure you it is not going to be trivial. IA64 asm instructions bundling 
and cycle optimization will have to be changed.
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