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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 9D7FFC0044D for ; Wed, 11 Mar 2020 21:30:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60C6520749 for ; Wed, 11 Mar 2020 21:30:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729394AbgCKVa1 (ORCPT ); Wed, 11 Mar 2020 17:30:27 -0400 Received: from vps-vb.mhejs.net ([37.28.154.113]:59626 "EHLO vps-vb.mhejs.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726579AbgCKVa0 (ORCPT ); Wed, 11 Mar 2020 17:30:26 -0400 Received: from MUA by vps-vb.mhejs.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.92.3) (envelope-from ) id 1jC8vm-0006Sy-LA; Wed, 11 Mar 2020 22:30:22 +0100 Subject: Re: [PATCH] cpuidle-haltpoll: allow force loading on hosts without the REALTIME hint To: Marcelo Tosatti Cc: "Rafael J. Wysocki" , Daniel Lezcano , Joao Martins , Boris Ostrovsky , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Konrad Rzeszutek Wilk References: <20200221174331.1480468-1-mail@maciej.szmigiero.name> <75d483b5-8edf-efb1-9642-ca367e2f1423@maciej.szmigiero.name> <2118832.28snYOIflM@kreacher> <20200310135006.GA6397@fuller.cnet> From: "Maciej S. Szmigiero" Autocrypt: addr=mail@maciej.szmigiero.name; prefer-encrypt=mutual; keydata= mQINBFpGusUBEADXUMM2t7y9sHhI79+2QUnDdpauIBjZDukPZArwD+sDlx5P+jxaZ13XjUQc 6oJdk+jpvKiyzlbKqlDtw/Y2Ob24tg1g/zvkHn8AVUwX+ZWWewSZ0vcwp7u/LvA+w2nJbIL1 N0/QUUdmxfkWTHhNqgkNX5hEmYqhwUPozFR0zblfD/6+XFR7VM9yT0fZPLqYLNOmGfqAXlxY m8nWmi+lxkd/PYqQQwOq6GQwxjRFEvSc09m/YPYo9hxh7a6s8hAP88YOf2PD8oBB1r5E7KGb Fv10Qss4CU/3zaiyRTExWwOJnTQdzSbtnM3S8/ZO/sL0FY/b4VLtlZzERAraxHdnPn8GgxYk oPtAqoyf52RkCabL9dsXPWYQjkwG8WEUPScHDy8Uoo6imQujshG23A99iPuXcWc/5ld9mIo/ Ee7kN50MOXwS4vCJSv0cMkVhh77CmGUv5++E/rPcbXPLTPeRVy6SHgdDhIj7elmx2Lgo0cyh uyxyBKSuzPvb61nh5EKAGL7kPqflNw7LJkInzHqKHDNu57rVuCHEx4yxcKNB4pdE2SgyPxs9 9W7Cz0q2Hd7Yu8GOXvMfQfrBiEV4q4PzidUtV6sLqVq0RMK7LEi0RiZpthwxz0IUFwRw2KS/ 9Kgs9LmOXYimodrV0pMxpVqcyTepmDSoWzyXNP2NL1+GuQtaTQARAQABtDBNYWNpZWogUy4g U3ptaWdpZXJvIDxtYWlsQG1hY2llai5zem1pZ2llcm8ubmFtZT6JAlQEEwEIAD4CGwMFCwkI BwIGFQoJCAsCBBYCAwECHgECF4AWIQRyeg1N257Z9gOb7O+Ef143kM4JdwUCXgY+twUJBDYq 8gAKCRCEf143kM4Jd/45D/wJvB7YuXuQvgqB9rG2b6cxMe2hriH9iLnpJlUjgzHwNDWkVF6v ZYJeIhYyUSxHNK/XExDS7UfH8E9Z7Jo9AoSlw+EBcUcw/HEwRI0DACicKemdJZVTsRn+sOC8 Imw/pWRyMHLy/Fc59xa68x7+6XFuABrcik05LTF6CDB/1EeUAPVY7mfQOpPUx4G72TZj93F5 30MnFj2PWJIiQ0T3MxDH02+TRdussTcaCy7opx5xOQER6kPIaQVKfNfEftT+p7B8Cr+jZJMo K7Lib6BnZJKXzYw0M8aB+qAbsipv/ctozOjzHLwTLuhpFcQV+ExccuWg53+pk71j9Pd+u8hq qNx9iNJtCb+jsbLbtoOtWpDLdTvSrXp7dQBCcqMs9CCBVPKdgyg+YPOcAgbGitygIpJCs0s9 5WRSv+lGmad14GDnp6c01kFnUqZ3G4B5/WLqmCFsIzZTnvW+kH5gw5PFBI0eD7s8Gf523NgX 0U2c1hEtFyW539v8b+5USIYgLNqFjhJ0u8Fp4re5TFI16/rG8Ts+fpsPzJGx5LcrD+OIqN7A VRIWAyNhUZpczp7e391R2MT4W1ee5lywt4YfC3/7ifBZ/lFZgsPmGRlhT+PT4ZBiTL6w8pP9 HT+KiMAtgvISfoOgeMQ5NE0+DIV615CEKXGtTGeeBoHOza2Oq5BSIPvKwbkBjQRaRrtSAQwA 1c8skXiNYGgitv7X8osxlkOGiqvy1WVV6jJsv068W6irDhVETSB6lSc7Qozk9podxjlrae9b vqfaJxsWhuwQjd+QKAvklWiLqw4dll2R3+aanBcRJcdZ9iw0T63ctD26xz84Wm7HIVhGOKsS yHHWJv2CVHjfD9ppxs62XuQNNb3vP3i7LEto9zT1Zwt6TKsJy5kWSjfRr+2eoSi0LIzBFaGN D8UOP8FdpS7MEkqUQPMI17E+02+5XCLh33yXgHFVyWUxChqL2r8y57iXBYE/9XF3j4+58oTD ne/3ef+6dwZGyqyP1C34vWoh/IBq2Ld4cKWhzOUXlqKJno0V6pR0UgnIJN7SchdZy5jd0Mrq yEI5k7fcQHJxLK6wvoQv3mogZok4ddLRJdADifE4+OMyKwzjLXtmjqNtW1iLGc/JjMXQxRi0 ksC8iTXgOjY0f7G4iMkgZkBfd1zqfS+5DfcGdxgpM0m9EZ1mhERRR80U6C+ZZ5VzXga2bj0o ZSumgODJABEBAAGJA/IEGAEIACYCGwIWIQRyeg1N257Z9gOb7O+Ef143kM4JdwUCXgY/uAUJ BDYrZgHAwPQgBBkBCAAdFiEE4ndqq6COJv9aG0oJUrHW6VHQzgcFAlpGu1IACgkQUrHW6VHQ zgdztQv+PRhCVQ7KUuQMEvMaH+rc1GIaHT6Igbvn77bEG1Kd39jX3lJDdyZXrVqxFylLu64r +9kHeCslM+Uq/fUM94od7cXGkvCW7ST1MUGQ3g+/rAf88F5l+KjUzLShw2sxElP+sjGQGQ4z Llve5MarGtV4TH6dJlDXZTtxwHotHZDiA2bUeJYLlMAggwLM/rBS9xfytMNuFk8U0THR/TVw vu3VymjdOjJnSecFyu9iRskRXc8LA9JxqDbfmETePg1dPehxiwgMvdi3WdYk4BB1wMl0MdnU 2Ea3AdjU3nX+Uc/npPMvDuzai9ZA7/tVG1RaQhIElL85+A5Tb2Wzl0IoO1kTafkaQNBOStEe O1fhLSz5/3Dt+dOOqxp7VuwSHqEXb3jc6WgnwZiimF8vvGzE2PNBAuIAwGItY2fkpGblbmmN b/qYZEjdbVNjfJXyVyez//QoiUrQk2sC9nNL7zYTEMocuJFN90a2158h5ve1qBT0jpUx69Ok yR8/DxnAEmj04WSoCRCEf143kM4Jd7OzEADUrk8wzAA0xcA90X0xp2FkANDA82fxCdnXYjQ/ IJW+GVupSQ/eWBzUprtb8tELSBnIWQ6bLv7vbetN1zPy+n6YeB0IVgwWoOObnT0BOeLleUsy KKBhtD6Vw3u5QxdpdGUIwPB39+NaBgo1Sh99fAVNv2ARNa12jzI2lRvVtWMdRkMaLclkMCpB Lw3UItHfwPhHhxwwfQ/s37acPHoxf+Jg3C0oDNAjNzOlDbuoa0sYlrJ17ExDuoH/SzGu+zAo XWIZG/JWQahS2HTLfjQDsLq0NdNfgPCpa7TZJIAimXAUqR1zKBJtDpbt5rdFJR9dHXipab/W rDKeBgMIgv8rwcJMFHwbr72ht/5imC3uInxCCI76w3MpxuHfXWzWsbOXwceZ9La3k/MHEGtc 05yGMerio0MZHJwRuG7wI4xBMt5LP6KMQcsEMdDQaiZxC3GgBAuU1ewdj6sKodCAUOFXBiXx ePW59LVYZVHCAwYXBoCgy0P1BpFbYNY5p0tzWakCSw94YC2yVjc+8xoJCdlBN3dHJStrOTQ4 P1nWwO5ELit0mW+yLtsumj0mlNs1EzSnhKhrci4YfOLOGV3Wnp/QqfVU1uArhC8yZ/FWBNau MKYJmFdTOS89DdqGx2/VjICOaG28GL75QXwcbViNJukN5kx0b6cGlnm9tr8DZ/4AHFDmBrkB jQRaRrwiAQwAxnVmJqeP9VUTISps+WbyYFYlMFfIurl7tzK74bc67KUBp+PHuDP9p4ZcJUGC 3UZJP85/GlUVdE1NairYWEJQUB7bpogTuzMI825QXIB9z842HwWfP2RW5eDtJMeujzJeFaUp meTG9snzaYxYN3r0TDKj5dZwSIThIMQpsmhH2zylkT0jH7kBPxb8IkCQ1c6wgKITwoHFjTIO 0B75U7bBNSDpXUaUDvd6T3xd1Fz57ujAvKHrZfWtaNSGwLmUYQAcFvrKDGPB5Z3ggkiTtkmW 3OCQbnIxGJJw/+HefYhB5/kCcpKUQ2RYcYgCZ0/WcES1xU5dnNe4i0a5gsOFSOYCpNCfTHtt VxKxZZTQ/rxjXwTuToXmTI4Nehn96t25DHZ0t9L9UEJ0yxH2y8Av4rtf75K2yAXFZa8dHnQg CkyjA/gs0ujGwD+Gs7dYQxP4i+rLhwBWD3mawJxLxY0vGwkG7k7npqanlsWlATHpOdqBMUiA R22hs02FikAoiXNgWTy7ABEBAAGJAjwEGAEIACYCGwwWIQRyeg1N257Z9gOb7O+Ef143kM4J dwUCXgZABwUJBDYq5QAKCRCEf143kM4Jd8WEEAC1D/p5Fi/YvVlUUBHhI+WS5c8SqdZaM//h r0RfyrUaKwU+XR+wB6HACwfvN3t0i7BhiER9s6UaMcxWzZfVZYcLcgaKvucHkQMkO+XxGcqE /7m0j7r4iERxCi3FZTNMLGjxzG2teWesUSbvtlrFMtc3lxwdAiA/kF8FBkesG7acP0saiIJr UcMfU+ZsXGxMSrZ4RRRFESvcgvK95KgnlsyuRouyVFu7tJVbTnW6/65JRFNlEQ6Wsbx/0C90 KWkF9R7DLtcVxno75+pXiXDdy9bq54uQeT+9dr+EdyVL0H3eTzP9js7GrRahuHD6/AxekQwX afDLYnExRXL7acu5a1fUpDKWe/CigtyjJz73Dvs9eV7Wvk69TFV60Ft84UEqNBqSha7s1/m8 tQW4InvfnL9h0LWVvwUZe5HKCPe65amwBOvwkkYd4OfNb0NDVudTMsCYLJ8al57zLelH2hcS wOiVdXBsbePjzLy2exEXUb1bHFjBoHnHX6uszBOzM/Dv1eNWJPZ3r3PRFnQk/D9ohEXVEmUI TLDd7lR06Nr8J4oG1RprRTW1T8xE6lSwbfsp9ApU1QuDZzSI1hdNpDYRVUmQeiXnSjR1YBVb zOyMU+hnnsQZMdTQ2qVFZs4JGCA9/wSOMMsohDbJNX2iGR1S+RFpZY9sipuGBVM7wIVrz4Ac Iw== Message-ID: Date: Wed, 11 Mar 2020 22:30:17 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200310135006.GA6397@fuller.cnet> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi Marcelo, On 10.03.2020 14:50, Marcelo Tosatti wrote: > On Wed, Mar 04, 2020 at 11:31:31AM +0100, Rafael J. Wysocki wrote: >> On Friday, February 28, 2020 6:10:18 PM CET Maciej S. Szmigiero wrote: >>> A friendly ping here. >>> >>> Maciej >>> >>> On 21.02.2020 18:43, Maciej S. Szmigiero wrote: >>>> From: "Maciej S. Szmigiero" >>>> >>>> Before commit 1328edca4a14 ("cpuidle-haltpoll: Enable kvm guest polling >>>> when dedicated physical CPUs are available") the cpuidle-haltpoll driver >>>> could also be used in scenarios when the host does not advertise the >>>> KVM_HINTS_REALTIME hint. >>>> >>>> While the behavior introduced by the aforementioned commit makes sense as >>>> the default there are cases where the old behavior is desired, for example, >>>> when other kernel changes triggered by presence by this hint are unwanted, >>>> for some workloads where the latency benefit from polling overweights the >>>> loss from idle CPU capacity that otherwise would be available, or just when >>>> running under older Qemu versions that lack this hint. >>>> >>>> Let's provide a typical "force" module parameter that allows restoring the >>>> old behavior. >>>> >>>> Signed-off-by: Maciej S. Szmigiero >>>> --- >>>> drivers/cpuidle/cpuidle-haltpoll.c | 12 +++++++++++- >>>> 1 file changed, 11 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c >>>> index b0ce9bc78113..07e5b36076bb 100644 >>>> --- a/drivers/cpuidle/cpuidle-haltpoll.c >>>> +++ b/drivers/cpuidle/cpuidle-haltpoll.c >>>> @@ -18,6 +18,11 @@ >>>> #include >>>> #include >>>> >>>> +static bool force __read_mostly; >>>> +module_param(force, bool, 0444); >>>> +MODULE_PARM_DESC(force, >>>> + "Load even if the host does not provide the REALTIME hint"); >> >> Why not to say "Load unconditionally" here? > > Makes sense to me. Can you ack the v2 patch that has all the review comments resolved then? It is available here: https://lore.kernel.org/kvm/20200304113248.1143057-1-mail@maciej.szmigiero.name/ Thanks, Maciej