Re: Add prefetch switch stack hook in scheduler function

From: Keith Owens
Date: Fri Jul 29 2005 - 02:58:48 EST

On Fri, 29 Jul 2005 00:22:43 -0700,
"Chen, Kenneth W" <kenneth.w.chen@xxxxxxxxx> wrote:
>On ia64, we have two kernel stacks, one for outgoing task, and one for
>incoming task. for outgoing task, we haven't called switch_to() yet.
>So the switch stack structure for 'current' will be allocated immediately
>below current 'sp' pointer. For the incoming task, it was fully ctx'ed out
>previously, so switch stack structure is immediate above kernel_stack(next).
>It Would be beneficial to prefetch both stacks.

struct switch_stack for current is all write data, no reading is done.
Is it worth doing prefetchw() for current? IOW, is there any
measurable performance gain?

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