On Wed, 2015-08-05 at 19:30 -0500, Segher Boessenkool wrote: > On Wed, Aug 05, 2015 at 03:29:35PM +0200, Christophe Leroy wrote: > > On the 8xx, load latency is 2 cycles and taking branches also takes > > 2 cycles. So let's unroll the loop. > > This is not true for most other 32-bit PowerPC; this patch makes > performance worse on e.g. 6xx/7xx/7xxx. Let's not!
Chips with a load latency greater than 2 cycles should also benefit from the unrolling. Have you benchmarked this somewhere and seen it reduce performance? Do you know of any 32-bit PPC chips with a load latency less than 2 cycles? -Scott -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
