On Mon, 2011-05-23 at 18:31 -0500, Scott Wood wrote:
> On Tue, 24 May 2011 06:51:01 +1000
> Benjamin Herrenschmidt wrote:
>
> > Is your linear mapping bolted ? If it is you may be able to cut out most
> > of the save/restore stuff (SRR0,1, ...) since with a normal walk you
> > won't take nested m
On Tue, 24 May 2011 06:51:01 +1000
Benjamin Herrenschmidt wrote:
> Is your linear mapping bolted ? If it is you may be able to cut out most
> of the save/restore stuff (SRR0,1, ...) since with a normal walk you
> won't take nested misses.
It is bolted -- we ignore anything we can't map with 16 e
On Mon, 2011-05-23 at 13:54 -0500, Scott Wood wrote:
> On Sat, 21 May 2011 08:15:36 +1000
> Benjamin Herrenschmidt wrote:
>
> > On Fri, 2011-05-20 at 15:57 -0500, Scott Wood wrote:
> >
> > > I see a 2% cost going from virtual pmd to full 4-level walk in the
> > > benchmark mentioned above (some
On Sat, 21 May 2011 08:15:36 +1000
Benjamin Herrenschmidt wrote:
> On Fri, 2011-05-20 at 15:57 -0500, Scott Wood wrote:
>
> > I see a 2% cost going from virtual pmd to full 4-level walk in the
> > benchmark mentioned above (some type of sort), and just under 3% in
> > page-stride lat_mem_rd from
On Fri, 2011-05-20 at 15:57 -0500, Scott Wood wrote:
> I see a 2% cost going from virtual pmd to full 4-level walk in the
> benchmark mentioned above (some type of sort), and just under 3% in
> page-stride lat_mem_rd from lmbench.
>
> OTOH, the virtual pmd approach still leaves the possibility of
On Thu, 19 May 2011 07:33:55 +1000
Benjamin Herrenschmidt wrote:
> On Wed, 2011-05-18 at 16:05 -0500, Scott Wood wrote:
> > Loads with non-linear access patterns were producing a very high
> > ratio of recursive pt faults to regular tlb misses. Rather than
> > choose between a 4-level table walk
On Wed, 2011-05-18 at 16:05 -0500, Scott Wood wrote:
> Loads with non-linear access patterns were producing a very high
> ratio of recursive pt faults to regular tlb misses. Rather than
> choose between a 4-level table walk or a 1-level virtual page table
> lookup, use a hybrid scheme with a virtu
Loads with non-linear access patterns were producing a very high
ratio of recursive pt faults to regular tlb misses. Rather than
choose between a 4-level table walk or a 1-level virtual page table
lookup, use a hybrid scheme with a virtual linear pmd, followed by a
2-level lookup in the normal han
