Re: [RFC PATCH 0/4]: affinity-on-next-touch

[Stefan Lankes]

Brice Goglin wrote:
> Lee Schermerhorn wrote:
> > The primary difference should be at unmap time, right?  In the fault
> > path, I only update the pte of the faulting task.  That's why I require
> > the [anon] pages to be in the swap cache [or something similar].  I
> > don't want to be fixing up other tasks' page tables in the context of
> > the faulting task's fault handler.  If, later, another task touches the
> > page, it will take a minor fault and find the [possibly migrated] page
> > in the cache.  Hmmm, I guess all tasks WILL incur the minor fault if
> > they touch the page after the unmap.  That could be part of the
> > difference if you compare on the same kernel version.
> >   
>
> Agreed.
>
> > Try booting with cgroup_disable=memory on the command line, if you have
> > the memory resource controller configured in.  See what that does to
> > your measurements.
> >   
>
> It doesn't seem to help. I'll try to bisect and find where the
> performance dropped.

I am not able to reconstruct any performance drawbacks on my system. 
Could you send me your low-level benchmark?

Stefan
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