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SubjectRe: PATCH 2.3.26: kmalloc GFP_ZERO
On Tue, Nov 09, 1999 at 10:40:50PM +0100, Andrea Arcangeli wrote:
> On Tue, 9 Nov 1999, David S. Miller wrote:
>
> >No, as Victor has stated you don't call standard memset, you inline
> >code it in the architecture specific idle loop and there you can
> >check need_resched in between every store instruction if you feel
> >it necessary.
>
> So you'll waste some more instruction cache with the start, stop, restart
> from last, stop, restart from last algorithm.

What a cost!
Nearly all optimizations are tradeoffs. In this case, you have a easy to show
significant decrease in wall clock time of an important benchmark versus the
terrible cost of using 2 cache lines in the instruction cache during a time period
in which you have nothing else to do.

See: http://www.cs.nmt.edu/~cort/papers/linuxppc-mm/



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