On 2/11/2014 8:41 AM, Peter Zijlstra wrote:

On Mon, Feb 03, 2014 at 08:17:47AM -0800, Arjan van de Ven wrote:

quoted

On 2/3/2014 6:56 AM, Peter Zijlstra wrote:
if there's a simple api like

sched_cpu_cache_wiped(int llc)

that would be very nice for this; the menuidle side knows this
for some cases and thus can just call it. This would be a very
small and minimal change

* if you don't care about llc vs core local caches then that
   parameter can go away

* I assume this is also called for the local cpu... if not then we
   need to add a cpu number argument

* we can also call this from architecture code when wbinvd or the
   arm equivalent is called etc

A little something like so?

is there value also in doing a cpu level cache flush?
(cpu cache flush we know from the C state, for the llc cache flush we need to read an MSR
on x86. Not insane expensive but not zero either)