Re: 50 Watt idle power regression bisected to Linux-3.10

From: Thomas Gleixner
Date: Wed Dec 11 2013 - 10:02:59 EST


On Wed, 11 Dec 2013, Ingo Molnar wrote:
>
> Another thing that is required I think is to issue a write barrier
> before CLFLUSH instruction. By my (possibly incorrect ...) reading of
> the documentation CLFLUSH does not appear to be ordered (at all), so
> it might execute before the modification to the affected memory?

We already have a write barrier in the code which modifies
current_thread_info()->flags.

Thanks,

tglx
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