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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 A5936C43144 for ; Tue, 26 Jun 2018 15:22:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6D7126D1A for ; Tue, 26 Jun 2018 15:22:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A6D7126D1A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=rjwysocki.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752017AbeFZPWF (ORCPT ); Tue, 26 Jun 2018 11:22:05 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:47911 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbeFZPWD (ORCPT ); Tue, 26 Jun 2018 11:22:03 -0400 Received: from 79.184.255.183.ipv4.supernova.orange.pl (79.184.255.183) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id 30a794575fddc1af; Tue, 26 Jun 2018 17:22:00 +0200 From: "Rafael J. Wysocki" To: Linux PM Cc: Linux Documentation , Srinivas Pandruvada , Jonathan Corbet , LKML Subject: [PATCH] Documentation: intel_pstate: Describe hwp_dynamic_boost sysfs knob Date: Tue, 26 Jun 2018 17:20:43 +0200 Message-ID: <306013127.TOMvMKusHN@aspire.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki Document the recently introduced hwp_dynamic_boost sysfs knob allowing user space to tell intel_pstate to use iowait boosting in the active mode with HWP enabled (to improve performance). Signed-off-by: Rafael J. Wysocki --- Documentation/admin-guide/pm/intel_pstate.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) Index: linux-pm/Documentation/admin-guide/pm/intel_pstate.rst =================================================================== --- linux-pm.orig/Documentation/admin-guide/pm/intel_pstate.rst +++ linux-pm/Documentation/admin-guide/pm/intel_pstate.rst @@ -378,6 +378,17 @@ argument is passed to the kernel in the but it affects the maximum possible value of per-policy P-state limits (see `Interpretation of Policy Attributes`_ below for details). +``hwp_dynamic_boost`` + This attribute is only present if ``intel_pstate`` works in the + `active mode with the HWP feature enabled `_ in + the processor. If set (equal to 1), it causes the minimum P-state limit + to be increased dynamically for a short time whenever a task previously + waiting on I/O is selected to run on a given logical CPU (the purpose + of this mechanism is to improve performance). + + This setting has no effect on logical CPUs whose minimum P-state limit + is directly set to the highest non-turbo P-state or above it. + .. _status_attr: ``status``