From patchwork Sat Oct 13 23:09:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peng Hao X-Patchwork-Id: 10640215 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D2A34933 for ; Sat, 13 Oct 2018 14:58:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C4C552AAB9 for ; Sat, 13 Oct 2018 14:58:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B95752AAF9; Sat, 13 Oct 2018 14:58:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5F9802AAD0 for ; Sat, 13 Oct 2018 14:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726352AbeJMWfu (ORCPT ); Sat, 13 Oct 2018 18:35:50 -0400 Received: from mxhk.zte.com.cn ([63.217.80.70]:31448 "EHLO mxhk.zte.com.cn" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726309AbeJMWfu (ORCPT ); Sat, 13 Oct 2018 18:35:50 -0400 Received: from mse01.zte.com.cn (unknown [10.30.3.20]) by Forcepoint Email with ESMTPS id 6E61D4F6CCA3374CBA73; Sat, 13 Oct 2018 22:58:17 +0800 (CST) Received: from notes_smtp.zte.com.cn ([10.30.1.239]) by mse01.zte.com.cn with ESMTP id w9DEwCcv096826; Sat, 13 Oct 2018 22:58:12 +0800 (GMT-8) (envelope-from peng.hao2@zte.com.cn) Received: from localhost.localdomain.localdomain ([10.74.120.59]) by szsmtp06.zte.com.cn (Lotus Domino Release 8.5.3FP6) with ESMTP id 2018101322585544-4289302 ; Sat, 13 Oct 2018 22:58:55 +0800 From: Peng Hao To: pbonzini@redhat.com, rkrcmar@redhat.com, stefanha@gmail.com Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Peng Hao Subject: [PATCH V5 0/3] introduce coalesced pio support Date: Sun, 14 Oct 2018 07:09:54 +0800 Message-Id: <1539472197-111085-1-git-send-email-peng.hao2@zte.com.cn> X-Mailer: git-send-email 1.8.3.1 X-MIMETrack: Itemize by SMTP Server on SZSMTP06/server/zte_ltd(Release 8.5.3FP6|November 21, 2013) at 2018-10-13 22:58:55, Serialize by Router on notes_smtp/zte_ltd(Release 9.0.1FP7|August 17, 2016) at 2018-10-13 22:57:52, Serialize complete at 2018-10-13 22:57:52 X-MAIL: mse01.zte.com.cn w9DEwCcv096826 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Coalesced pio is based on coalesced mmio and can be used for some port like rtc port, pci-host config port and so on. Specially in case of rtc as coalesced pio, some versions of windows guest access rtc frequently because of rtc as system tick. guest access rtc like this: write register index to 0x70, then write or read data from 0x71. writing 0x70 port is just as index and do nothing else. So we can use coalesced pio to handle this scene to reduce VM-EXIT time. When starting and closing a virtual machine, it will access pci-host config port frequently. So setting these port as coalesced pio can reduce startup and shutdown time. without my patch, get the vm-exit time of accessing rtc 0x70 and piix 0xcf8 using perf tools: (guest OS : windows 7 64bit) IO Port Access Samples Samples% Time% Min Time Max Time Avg time 0x70:POUT 86 30.99% 74.59% 9us 29us 10.75us (+- 3.41%) 0xcf8:POUT 1119 2.60% 2.12% 2.79us 56.83us 3.41us (+- 2.23%) with my patch IO Port Access Samples Samples% Time% Min Time Max Time Avg time 0x70:POUT 106 32.02% 29.47% 0us 10us 1.57us (+- 7.38%) 0xcf8:POUT 1065 1.67% 0.28% 0.41us 65.44us 0.66us (+- 10.55%) Peng Hao (3): kvm/x86 : add coalesced pio support kvm/x86 : add document for coalesced mmio kvm/x86 : add document for coalesced pio Documentation/virtual/kvm/api.txt | 28 +++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 11 +++++++++-- virt/kvm/coalesced_mmio.c | 12 +++++++++--- virt/kvm/kvm_main.c | 2 ++ 4 files changed, 48 insertions(+), 5 deletions(-)