On Wed, 17 Jul 2013 09:21:00 +0200 Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * 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.
Spose so, if you really think it's worth it. It's all downside for
uniprocessor machines. And for architectures which don't implement the
counters, of course.
> > --- linux.git/include/linux/vm_event_item.h~tlb-vmstats 2013-07-16 16:41:56.478280438 -0700
> > +++ linux.git-davehans/include/linux/vm_event_item.h 2013-07-16 16:41:56.483280658 -0700
> > @@ -70,6 +70,11 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
> > THP_ZERO_PAGE_ALLOC,
> > THP_ZERO_PAGE_ALLOC_FAILED,
> > #endif
> >
> > + NR_TLB_REMOTE_FLUSH, /* cpu tried to flush others' tlbs */
> > + NR_TLB_REMOTE_FLUSH_RECEIVED,/* cpu received ipi for flush */
> > + NR_TLB_LOCAL_FLUSH_ALL,
> > + NR_TLB_LOCAL_FLUSH_ONE,
> > + NR_TLB_LOCAL_FLUSH_ONE_KERNEL,
>
> Please fix the vertical alignment of comments.
I looked - this isn't practical.
It would be nice to actually document these things though. We don't
*have* to squeeze the comment into the RHS.
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