Re: [PATCH v2 2/2] powerpc32: optimise csum_partial() loop

From: Segher Boessenkool
Date: Wed Aug 05 2015 - 20:32:24 EST


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!


Segher
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/