From: Bandan Das <bsd@redhat.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Subject: [RFC PATCH 0/2] Emulator speedups - avoid initializations where possible
Date: Thu,  3 Apr 2014 18:27:48 -0400
Message-Id: <1396564070-5586-1-git-send-email-bsd@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org

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 :
http://comments.gmane.org/gmane.linux.kernel/1676101

Before:
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

After:
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(-)

-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/