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Date:	Thu,  3 Apr 2014 18:27:48 -0400
From:	Bandan Das <>
Cc:, Paolo Bonzini <>
Subject: [RFC PATCH 0/2] Emulator speedups - avoid initializations where possible

While initializing emulation context structure, kvm memsets to 0 a 
number of fields some of which are redundant since they get set eventually.
This patch attempts at avoiding some of them.

Here are some before/after numbers on a Haswell host
Note : The before numbers already include Paolo's RFC posted here :

667 cycles/emulated jump instruction
839 cycles/emulated move instruction
892 cycles/emulated arithmetic instruction
995 cycles/emulated memory load instruction
1026 cycles/emulated memory store instruction
1022 cycles/emulated memory RMW instruction

639 cycles/emulated jump instruction
786 cycles/emulated move instruction
802 cycles/emulated arithmetic instruction
936 cycles/emulated memory load instruction
970 cycles/emulated memory store instruction
1000 cycles/emulated memory RMW instruction

Bandan Das (2):
  KVM: emulate: move init_decode_cache to emulate.c
  KVM: emulate: clean up initializations in init_decode_cache

 arch/x86/include/asm/kvm_emulate.h | 17 +++++++------
 arch/x86/kvm/emulate.c             | 49 ++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/x86.c                 | 13 ----------
 3 files changed, 59 insertions(+), 20 deletions(-)


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