Re: [PATCH v7 8/8] x86/tlb: just do tlb flush on one of siblingsof SMT

[Peter Zijlstra]

On Wed, 2012-05-23 at 18:46 -0700, Andrew Lutomirski wrote:
> On Wed, May 23, 2012 at 10:15 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > On Wed, 2012-05-23 at 19:09 +0200, Peter Zijlstra wrote:
> >> > There is no comment or anything else indicating that this is
> >> > suitable for dual-thread CPUs only - when there are more than
> >> > 2 threads per core, the intended effect won't be achieved.
> >>
> >> Why would that be? Won't higher thread count still share the same
> >> resources just more so?
> >
> > Ah, I see, you're saying his code is buggy for >2 threads. Agreed.
> >
> 
> An evil knob to statically choose which SMT sibling gets the interrupt
> would be nice.  Then my compute-intensive thread could be (mostly)
> unaffected by the other thread on a different core that calls munmap
> frequently.

Just make sure the two workloads never share a core and this should
already happen since TLB invalidates are only broadcast to the mm
cpumask.

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