Re: [RESEND][PATCH] mm: vmstats: tlb flush counters

From: Raghavendra KT
Date: Fri Jul 19 2013 - 07:38:13 EST


On Wed, Jul 17, 2013 at 5:14 AM, Dave Hansen <dave@xxxxxxxx> wrote:
>
> I was investigating some TLB flush scaling issues and realized
> that we do not have any good methods for figuring out how many
> TLB flushes we are doing.
>
> It would be nice to be able to do these in generic code, but the
> arch-independent calls don't explicitly specify whether we
> actually need to do remote flushes or not. In the end, we really
> need to know if we actually _did_ global vs. local invalidations,
> so that leaves us with few options other than to muck with the
> counters from arch-specific code.
>
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> ---

Hi Dave,
While measuring non - PLE performance, one of the bottleneck, I am seeing is
flush tlbs.
perf had helped in alaysing a bit there, but this patch would help
in precise calculation. It will aslo help in tuning the PLE window
experiments (larger PLE window
would affect remote flush TLBs)

Thanks for this patch. Tested the patch on my sandybridge.box

Tested-by: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>
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