Re: [PATCH v5 6/7] x86/tlb: optimizing flush_tlb_mm

From: Steven Rostedt
Date: Tue May 15 2012 - 09:39:09 EST


On Tue, 2012-05-15 at 15:06 +0200, Peter Zijlstra wrote:
> On Tue, 2012-05-15 at 20:58 +0800, Luming Yu wrote:
> >
> >
> > Both __native_flush_tlb() and __native_flush_tlb_single(...)
> > introduced roughly 1 ns latency to tsc sampling executed in
> > stop_machine_context in two logical CPUs
>
> But you have to weight that against the cost of re-population, and
> that's the difficult bit, since we have no clue how many tlb entries are
> in use by the current cr3.
>
> It might be possible for intel to give us this information, I've asked
> for something similar for cachelines.

What information? The # of tlb entries in use?

-- Steve


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