Re: [PATCH 05/16] sched: SCHED_DEADLINE policy implementation.

From: Steven Rostedt
Date: Mon Apr 23 2012 - 21:04:04 EST

On Mon, 2012-04-23 at 23:58 +0200, Peter Zijlstra wrote:
> On Mon, 2012-04-23 at 22:55 +0100, Tommaso Cucinotta wrote:
> > why not write this straight in asm, i.e., multiply 64*64 then divide by
> > 64 keeping the intermediate result on 128 bits?
> If you know of a way to do this for all 30 odd architectures supported
> by our beloved kernel, do let me know ;-)
> Yes I can do it for x86_64, but people tend to get mighty upset if you
> break the compile for all other arches...

Use the draconian method. Make SCHED_DEADLINE dependent on
"ARCH_HAS_128_MULT" and any arch maintainer that wants SCHED_DEADLINE
for their arch will be responsible for implementing it ;-)

-- Steve

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