Nick Piggin discovered that lwsync barriers around locks were faster than isync
on 970. That was a long time ago and I completely dropped the ball in testing
his patches across other ppc64 processors.
Turns out the idea helps on other chips. Using a microbenchmark that
uses a lot of threads to contend on a global pthread mutex (and therefore a
global futex), POWER6 improves 8% and POWER7 improves 2%. I checked POWER5
and while I couldn't measure an improvement, there was no regression.
This patch uses the lwsync patching code to replace the isyncs with lwsyncs
on CPUs that support the instruction. We were marking POWER3 and RS64 as lwsync
capable but in reality they treat it as a full sync (ie slow). Remove the
CPU_FTR_LWSYNC bit from these CPUs so they continue to use the faster isync
method.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
BestComm, a DMA engine in MPC52xx SoC, requires snooping when
CPU caches are enabled to work properly.
Adding CPU_FTR_NEED_COHERENT fixes NFS problems on MPC52xx machines
introduced by 'powerpc/mm: Fix handling of _PAGE_COHERENT in BAT setup
code' (sha1: 4c456a67f5).
Signed-off-by: Piotr Ziecik <kosmo@semihalf.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The e500mc supports the new msgsnd/doorbell mechanisms that were added in
the Power ISA 2.05 architecture. We use the normal level doorbell for
doing SMP IPIs at this point.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
We're soon running out of CPU features and I need to add some new
ones for various MMU related bits, so this patch separates the MMU
features from the CPU features. I moved over the 32-bit MMU related
ones, added base features for MMU type families, but didn't move
over any 64-bit only feature yet.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds supports to the "extended" DCR addressing via the indirect
mfdcrx/mtdcrx instructions supported by some 4xx cores (440H6 and
later).
I enabled the feature for now only on AMCC 460 chips.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We were missing the CPU_FTR_NOEXECUTE bit in our cputable for all
these processors. The result is that update_mmu_cache() would flush
the cache for all pages mapped to userspace which is totally
unnecessary on those processors since we already handle flushing
on execute in the page fault path.
This should provide a nice speed up ;-)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Add a new CPU feature bit, CPU_FTR_UNALIGNED_LD_STD, to be added
to the 64bit powerpc chips that can do unaligned load double and
store double without any performance hit.
This is added to Power6 and Cell and will be used in the next commit
to disable the code that gets the destination address aligned on
those CPUs where doing that doesn't improve performance.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Add a new CPU feature bit, CPU_FTR_CP_USE_DCBTZ, to be added to the
64bit powerpc chips that benefit from having dcbt and dcbz
instructions used in their memory copy routines.
This will be used in a subsequent patch that updates copy_4K_page().
The new bit is added to Cell, PPC970 and Power4 because they show
better performance with the new copy_4K_page() when dcbt and dcbz
instructions are used.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The file arch/powerpc/kernel/sysfs.c is currently only compiled for
64-bit kernels. It contain code to register CPU sysdevs in sysfs and
add various properties such as cache topology and raw access by root
to performance monitor counters (PMCs). A lot of that can be re-used
as is on 32-bits.
This makes the file be built for both, with appropriate ifdef'ing
for the few bits that are really 64-bit specific, and adds some
support for the raw PMCs for 75x and 74xx processors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Anton Blanchard