[PATCH] Faster MMU lookups for Book3s

Alexander Graf agraf at suse.de
Sat Jun 26 09:16:55 EST 2010


Book3s suffered from my really bad shadow MMU implementation so far. So
I finally got around to implement a combined hash and list mechanism that
allows for much faster lookup of mapped pages.

To show that it really is faster, I tried to run simple process spawning
code inside the guest with and without these patches:

[without]

debian-powerpc:~# time for i in {1..1000}; do /bin/echo hello > /dev/null; done

real    0m20.235s
user    0m10.418s
sys     0m9.766s

[with]

debian-powerpc:~# time for i in {1..1000}; do /bin/echo hello > /dev/null; done

real    0m14.659s
user    0m8.967s
sys     0m5.688s

So as you can see, performance improved significantly.

Alexander Graf (2):
  KVM: PPC: Add generic hpte management functions
  KVM: PPC: Make use of hash based Shadow MMU

 arch/powerpc/include/asm/kvm_book3s.h |    7 +
 arch/powerpc/include/asm/kvm_host.h   |   18 ++-
 arch/powerpc/kvm/Makefile             |    2 +
 arch/powerpc/kvm/book3s_32_mmu_host.c |  104 ++-----------
 arch/powerpc/kvm/book3s_64_mmu_host.c |   98 +-----------
 arch/powerpc/kvm/book3s_mmu_hpte.c    |  286 +++++++++++++++++++++++++++++++++
 6 files changed, 327 insertions(+), 188 deletions(-)
 create mode 100644 arch/powerpc/kvm/book3s_mmu_hpte.c



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