From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 3797A454AA; Wed, 19 Jun 2024 16:57:09 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 27D4740291; Wed, 19 Jun 2024 16:57:09 +0200 (CEST) Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) by mails.dpdk.org (Postfix) with ESMTP id 960B240289 for ; Wed, 19 Jun 2024 16:57:08 +0200 (CEST) Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-1f9b52ef481so5475105ad.1 for ; Wed, 19 Jun 2024 07:57:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1718809028; x=1719413828; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=qjV99x/g9xBC2IDmuNnA0kR/Tubvm9VAgXmfsb6Angc=; b=QSIOXx18dOkClGbVA4PlGSAAFF/yrkrGWJaS9gEkRJiVNjNvsEvk/9qd6gsNP5a8me aSLZqEpq9IfhLPmcrAmecVz/h2v9P2+q2YLbl+hS3RVrpEvGplJEIJUyp/Ri6Fyb0NQf hO8s25bcohC8PLpF+3Ymj9Sgt1wUWO8st5P4p9yhgwAshxSKcqRbxwJ686s8kc/cRcYn +6EcSnfDXHEb+t5yDIa4zhn4+Jk4xBiscuZ2fYAfA92kmYCsC+H6a9cIIUkRSTHdDlNG MP/8eeQKOQdjIaAqmX8CngPJ5+7DAF3itOCSKzJ0ErOrZaSsGlSFbNDELqe4Fzqq3HQq DUkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718809028; x=1719413828; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=qjV99x/g9xBC2IDmuNnA0kR/Tubvm9VAgXmfsb6Angc=; b=NkTtFz/k1v/lCz3DezssXZ+kA+FMT8o/m5Z8APbnbouSqCcCGenXwJHfly8UUHo65s lah5gjowX5peJ6dCCO7696Ck6/46tPipC9IXa0zd7gFBHHKgpihcOUd28gQDMOoeBIoH GLwC9iZdihz8hi7Mel9fBcjqB7G1pWTWmiO6RO6bVbBbIiRf/zuFZmq9FIEV+b6w+1ai Mtdl7I2DwBDLpr3ej//rBaOr4daZaKy3zfSjhBxynmRrG5FHP560k4cSUSZlNVmBRqLB NQM9M5Lx6vwH4INSZIdH0J2nkVf7EUQyHqn8l/J6NSnLPIShbOeWJw+kPHraFKqtCKHF ia0g== X-Gm-Message-State: AOJu0YydpR1EvwAi1B3PRlsIug6RBTc48Z34pS23/IaNsqeBGBecfgQy iShI1eJVIQgkbvSiW6hTc35y4pbfnwr66qcnszSsErNJSrgnMWrJclBSkQPuNHU= X-Google-Smtp-Source: AGHT+IFfKzu1aMxTs17lpwbU5a0c0xKP9vDzuzfSPPr97De5uMzKxP0oObLgK392xvsXS0Fknl2jpA== X-Received: by 2002:a17:902:d2cc:b0:1f7:3f66:fc7b with SMTP id d9443c01a7336-1f9aa3db55fmr31321155ad.16.1718809027677; Wed, 19 Jun 2024 07:57:07 -0700 (PDT) Received: from hermes.local (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f9b522d8adsm13307535ad.33.2024.06.19.07.57.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Jun 2024 07:57:07 -0700 (PDT) Date: Wed, 19 Jun 2024 07:56:58 -0700 From: Stephen Hemminger To: Huisong Li Cc: , , , , , , , , Subject: Re: [PATCH v3 1/2] power: introduce PM QoS API on CPU wide Message-ID: <20240619075658.78ccb370@hermes.local> In-Reply-To: <20240619063144.20733-2-lihuisong@huawei.com> References: <20240320105529.5626-1-lihuisong@huawei.com> <20240619063144.20733-1-lihuisong@huawei.com> <20240619063144.20733-2-lihuisong@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Wed, 19 Jun 2024 14:31:43 +0800 Huisong Li wrote: > +PM QoS > +------ > + > +The deeper the idle state, the lower the power consumption, but the longer > +the resume time. Some service are delay sensitive and very except the low > +resume time, like interrupt packet receiving mode. > + > +And the "/sys/devices/system/cpu/cpuX/power/pm_qos_resume_latency_us" sysfs > +interface is used to set and get the resume latency limit on the cpuX for > +userspace. Each cpuidle governor in Linux select which idle state to enter > +based on this CPU resume latency in their idle task. > + > +The per-CPU PM QoS API can be used to set and get the CPU resume latency. > + > +The ``rte_power_qos_set_cpu_resume_latency()`` function can effect the work > +CPU's idle state selection and just allow to enter the shallowest idle state > +if set to zero (strict resume latency) for this CPU. > + > +The ``rte_power_qos_get_cpu_resume_latency()`` function can obtain the resume > +latency on specified CPU. > + Wording of this is hard to read and needs to be reworded for clarity. Explain more what PM QoS is to the user. Also, not sure if details about sysfs implementation is helpful. Should also say this is Linux only.