From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753863AbaEFSQ0 (ORCPT ); Tue, 6 May 2014 14:16:26 -0400 Received: from mail-ee0-f50.google.com ([74.125.83.50]:44490 "EHLO mail-ee0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752176AbaEFSQW (ORCPT ); Tue, 6 May 2014 14:16:22 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, bsd@redhat.com Subject: [RFC PATCH 0/4] KVM: emulator: speed up instruction fetch Date: Tue, 6 May 2014 20:16:11 +0200 Message-Id: <1399400175-23754-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This small series provides another ~6% speedup on top of Bandan's patches. It does so by speeding up instruction fetches. The three tricks, one per patch, are to help the compiler a bit by redistributing the work between do_insn_fetch_byte and do_insn_fetch, to avoid repeated checks on the boundary of the fetch cache, and to exploit the processor's support for unaligned accesses. Before: 819 cycles/emulated jump instruction 1020 cycles/emulated move instruction 1026 cycles/emulated arithmetic instruction 1264 cycles/emulated memory load instruction 1182 cycles/emulated memory store instruction 1299 cycles/emulated memory RMW instruction After: 771 cycles/emulated jump instruction 963 cycles/emulated move instruction 960 cycles/emulated arithmetic instruction 1192 cycles/emulated memory load instruction 1110 cycles/emulated memory store instruction 1228 cycles/emulated memory RMW instruction Paolo Bonzini (4): KVM: emulate: speed up do_insn_fetch KVM: emulate: avoid repeated calls to do_insn_fetch_bytes KVM: emulate: avoid per-byte copying in instruction fetches KVM: emulate: put pointers in the fetch_cache arch/x86/include/asm/kvm_emulate.h | 4 +- arch/x86/kvm/emulate.c | 97 ++++++++++++++++++++------------------ arch/x86/kvm/trace.h | 6 +-- 3 files changed, 57 insertions(+), 50 deletions(-) -- 1.8.3.1