On Sat, 21 May 2011 08:15:36 +1000
Benjamin Herrenschmidt b...@kernel.crashing.org 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
On Mon, 2011-05-23 at 13:54 -0500, Scott Wood wrote:
On Sat, 21 May 2011 08:15:36 +1000
Benjamin Herrenschmidt b...@kernel.crashing.org 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
On Tue, 24 May 2011 06:51:01 +1000
Benjamin Herrenschmidt b...@kernel.crashing.org 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
On Mon, 2011-05-23 at 18:31 -0500, Scott Wood wrote:
On Tue, 24 May 2011 06:51:01 +1000
Benjamin Herrenschmidt b...@kernel.crashing.org 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
On Thu, 19 May 2011 07:33:55 +1000
Benjamin Herrenschmidt b...@kernel.crashing.org 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
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
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
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 virtual
