Messages in this thread | | | Date | Wed, 22 Aug 2012 06:23:01 -0700 | From | Arjan van de Ven <> | Subject | Re: [discussion]sched: a rough proposal to enable power saving in scheduler |
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On 8/22/2012 6:21 AM, Matthew Garrett wrote: > On Wed, Aug 22, 2012 at 06:02:48AM -0700, Arjan van de Ven wrote: >> On 8/21/2012 10:41 PM, Mike Galbraith wrote: >>> For my dinky dual core laptop, I suspect you're right, but for a more >>> powerful laptop, I'd expect spread/don't to be noticeable. >> >> yeah if you don't spread, you will waste some power. >> but.. current linux behavior is to spread. >> so we can only make it worse. > > Right. For a single socket system the only thing you can do is use two > threads in preference to using two cores. That'll keep an extra core in > a deep C state for longer, at the cost of keeping the package out of a > deep C state for longer. There might be a win if the two processes > benefit from improved L1 cache locality, or if you're talking about
basically "if HT sharing would be good for performance" ;-)
(btw this is good news, it means this is not an actual power/performance tradeoff, but a "get it right" tradeoff)
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