[tremor] [PATCH] 12% global performance gain on a StrongARM

[Nicolas Pitre]

On Thu, 19 Sep 2002, Chris Gilbert wrote:

> > In some cases, the compiler would have inverted the two assignments.
> > However *x really needs to be written to memory first since the value of
> > y1  is still being processed in the pipeline by the smlal instruction.
> > The  memory barrier ensure that ordering.
> 
> Wouldn't it be better to push the result storing into the asm, to be
> certain that the ordering is always enforced correctly, and the correct
> number of cycles is waited?  Although I'm surprised that the processor
> doesn't actually do a stall to wait for the result.

It does, but the idea is to fill the pipeline with useful work instead of 
just stalling and wasting cycles.

<p>Nicolas

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