From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 057BACA9EA0 for ; Fri, 25 Oct 2019 14:05:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C387021D7B for ; Fri, 25 Oct 2019 14:05:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=virtuozzo.com header.i=@virtuozzo.com header.b="sIMUaT4R" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395307AbfJYOFq (ORCPT ); Fri, 25 Oct 2019 10:05:46 -0400 Received: from mail-bgr052101128031.outbound.protection.outlook.com ([52.101.128.31]:43597 "EHLO EUR01-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2391167AbfJYOFp (ORCPT ); Fri, 25 Oct 2019 10:05:45 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=oKSmbkvHFBTaJ2LP68E+948gn0YXjwxehlBbLpOJi2f9rWBF4mUmyaWRkKhiX6SlRskKB1TTPiZWYcLOZxJMAdFkDZwuMcK/haP2MvpzoazNC9GgIzT2qWrtxp8WMlmGUflZSkJcve6aJ/p64snwpNZ9NgQsKXwFjpQnRHB9CPuKA5pMoe2ub/YJ7jIAXNmuXCrrX4ADJVlQVkHz/vbVGqSBvswQ+x7bdHJZX1C3iwKaMOOoZSz4fhttsLOSCfqOxOOWVY9AhcMhAs8wJmCuyaXb/gE2VFDl6k+ZCospQDJjOagHXHm3BJe0UzVk1VIqfTN/vuRuhrXrxwLWD6Tx9A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2O/r+LuFaXM2GSlpXuXYCqLV/rv/L1195FjopVoNzMc=; b=DTX0zIhQKvzddaV7SYjr8IMBOIWfXTnLhRETV3DwLK/xJvd3s8pYK9YQS+0z0scAU4Vk8ePCFCC65BqCqLqazg9ByLIP7g7NWgG6FE6LlgGDD1YD1x0XKY6k6Yu4YX1pgb4HRNR4tKNb8W7o07xKmKKoSbxqhAoC9YhwCpa9IMcm4Xbr1Uaq1IpW3ZtyqMTYqxAFahvcmZlC4enFJO8nz8PgbMWYS13op+lp31FCxjzWYIH+pUoC2C5Fjt/oQZADEGoNUm27dhDdMcyRkmZggSP/xWsl+PfjHNIX4WTPXwrn6jOoUkdgxFFMsrxAw9c5xAGZKeSTpzEoay4VilLxbA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=virtuozzo.com; dmarc=pass action=none header.from=virtuozzo.com; dkim=pass header.d=virtuozzo.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2O/r+LuFaXM2GSlpXuXYCqLV/rv/L1195FjopVoNzMc=; b=sIMUaT4RjjIgBcxgSJU8tSyvPvP1IC0tgik9h6NiaVj6R7flGAsCAgsh7TkUZ8+bp7PQTRvd88HExB8eJRvHgBS8j1N4mdEwIn1tNxPjccCKvsX6bpfpLgyieCW09wrW8jd3nAPgCiBWLeF0Nam2caZY0ZYUff4DHRws+9lvQOI= Received: from AM4PR0802MB2242.eurprd08.prod.outlook.com (10.172.218.15) by AM4PR0802MB2305.eurprd08.prod.outlook.com (10.172.218.14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2347.18; Fri, 25 Oct 2019 14:05:34 +0000 Received: from AM4PR0802MB2242.eurprd08.prod.outlook.com ([fe80::9c3e:dc5:e056:9f89]) by AM4PR0802MB2242.eurprd08.prod.outlook.com ([fe80::9c3e:dc5:e056:9f89%12]) with mapi id 15.20.2387.023; Fri, 25 Oct 2019 14:05:34 +0000 From: Roman Kagan To: Vitaly Kuznetsov CC: "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Michael Kelley , Joe Perches Subject: Re: [PATCH v2] x86/hyper-v: micro-optimize send_ipi_one case Thread-Topic: [PATCH v2] x86/hyper-v: micro-optimize send_ipi_one case Thread-Index: AQHVizZYGDIi3UW4YkWmU3NiXuLPeqdrZBUA Date: Fri, 25 Oct 2019 14:05:34 +0000 Message-ID: <20191025140528.GB23240@rkaganb.sw.ru> References: <20191025131546.18794-1-vkuznets@redhat.com> In-Reply-To: <20191025131546.18794-1-vkuznets@redhat.com> Accept-Language: en-US, ru-RU Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mutt/1.12.1 (2019-06-15) mail-followup-to: Roman Kagan , Vitaly Kuznetsov , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Michael Kelley , Joe Perches x-originating-ip: [185.231.240.5] x-clientproxiedby: HE1PR05CA0207.eurprd05.prod.outlook.com (2603:10a6:3:f9::31) To AM4PR0802MB2242.eurprd08.prod.outlook.com (2603:10a6:200:5f::15) authentication-results: spf=none (sender IP is ) smtp.mailfrom=rkagan@virtuozzo.com; x-ms-exchange-messagesentrepresentingtype: 1 x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 9c7f713f-f0ae-4066-f730-08d759546743 x-ms-traffictypediagnostic: AM4PR0802MB2305:|AM4PR0802MB2305:|AM4PR0802MB2305: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:7691; x-forefront-prvs: 02015246A9 x-forefront-antispam-report: SFV:SPM;SFS:(10019020)(376002)(346002)(136003)(366004)(396003)(39840400004)(189003)(199004)(25786009)(6436002)(6486002)(52116002)(6512007)(9686003)(186003)(26005)(476003)(6916009)(102836004)(11346002)(446003)(386003)(6506007)(229853002)(486006)(66946007)(478600001)(66446008)(64756008)(66556008)(66476007)(14444005)(81166006)(8676002)(81156014)(8936002)(76176011)(256004)(305945005)(7736002)(7416002)(99286004)(58126008)(316002)(71200400001)(71190400001)(6116002)(86362001)(66066001)(3846002)(2906002)(33656002)(5660300002)(4326008)(1076003)(4744005)(6246003)(14454004)(54906003)(36756003)(30126002);DIR:OUT;SFP:1501;SCL:5;SRVR:AM4PR0802MB2305;H:AM4PR0802MB2242.eurprd08.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: virtuozzo.com does not designate permitted sender hosts) x-ms-exchange-transport-forked: True x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 8pd8kFQkHqtKZKOvPSqIYz4JlrN0v97YFj/WKQVwk5y2PCvgvkzXVkFG4WwPcbO79f1Lu2SiECdPuadYhSEo33GyTLy/pjn5F0mAYjw+fnu9rQFlG3rzQ2dz5WN8TEVRAqrUlaDA7uMHnJ7tpJx0uCVMYc+3RAD0xrWVEs8Pz4ygmX7vn+GnEdNkHiyJB+flE5j1DtWZq364U4Mf65NKNx/D2pHVooKaf1BXRu8phI5tUB4mwVGSlearY90A8VrOoHVGGN7vfl7xwuwedSRWf7iwEZIBh410YIUt8bEaZM2k3ceb/YrCk4ahGFCbmOkEHpvawMynCsR4MgxVxb5/mHr5Yp83IOeAHFFfXHWdL3JLS2lFbMB5k4Yih2seVqybn6tFXnuZhEFNOs7G7yCWO2ucmRK79rRXQmjgFPB8g7JLYmsJjPBVxKQdHUgrctptQ3EDDiwsmLzPffoRfanCC/2z4aOv1rZdGgPfuCFRIMazCmU1Bhop25CdCNCz7XrA8y9OBCBcytvcED7ES6mKwg== Content-Type: text/plain; charset="us-ascii" Content-ID: <7910855E4302C34FB54E12C5C8111618@eurprd08.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-Network-Message-Id: 9c7f713f-f0ae-4066-f730-08d759546743 X-MS-Exchange-CrossTenant-originalarrivaltime: 25 Oct 2019 14:05:34.3785 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: iFCAnhKManmWYXAW1ARwqbi7ni1EVTlvJ+JfDcDjTBmCvyohSSEIYZZ0APM0rm7dSOVHEuCRpX1jq1kT5kULHA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM4PR0802MB2305 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Fri, Oct 25, 2019 at 03:15:46PM +0200, Vitaly Kuznetsov wrote: > When sending an IPI to a single CPU there is no need to deal with cpumasks. > With 2 CPU guest on WS2019 I'm seeing a minor (like 3%, 8043 -> 7761 CPU > cycles) improvement with smp_call_function_single() loop benchmark. The > optimization, however, is tiny and straitforward. Also, send_ipi_one() is > important for PV spinlock kick. > > I was also wondering if it would make sense to switch to using regular > APIC IPI send for CPU > 64 case but no, it is twice as expesive (12650 CPU > cycles for __send_ipi_mask_ex() call, 26000 for orig_apic.send_IPI(cpu, > vector)). > > Signed-off-by: Vitaly Kuznetsov > --- > Changes since v1: > - Style changes [Roman, Joe] > --- > arch/x86/hyperv/hv_apic.c | 13 ++++++++++--- > arch/x86/include/asm/trace/hyperv.h | 15 +++++++++++++++ > 2 files changed, 25 insertions(+), 3 deletions(-) Reviewed-by: Roman Kagan