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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT 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 B20C6C43219 for ; Mon, 29 Apr 2019 08:03:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 833652054F for ; Mon, 29 Apr 2019 08:03:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727549AbfD2IDe (ORCPT ); Mon, 29 Apr 2019 04:03:34 -0400 Received: from mga06.intel.com ([134.134.136.31]:59379 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726718AbfD2IDb (ORCPT ); Mon, 29 Apr 2019 04:03:31 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Apr 2019 01:03:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,408,1549958400"; d="scan'208";a="139699412" Received: from shbuild999.sh.intel.com ([10.239.146.112]) by orsmga006.jf.intel.com with ESMTP; 29 Apr 2019 01:03:28 -0700 From: Feng Tang To: Andrew Morton , Arjan van de Ven , Jonathan Corbet , Ingo Molnar , Eric W Biederman , Peter Zijlstra , Dmitry Vyukov , Thomas Gleixner , Andy Lutomirski , Ying Huang , linux-kernel@vger.kernel.org Cc: Feng Tang Subject: [RFC PATCH 1/3] kernel/sysctl: add description for "latencytop" Date: Mon, 29 Apr 2019 16:03:29 +0800 Message-Id: <1556525011-28022-2-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1556525011-28022-1-git-send-email-feng.tang@intel.com> References: <1556525011-28022-1-git-send-email-feng.tang@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The body of description is mostly copied from comments in kernel/latencytop.c Cc: Arjan van de Ven Cc: Jonathan Corbet Signed-off-by: Feng Tang --- Documentation/sysctl/kernel.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index c0527d8..080ef66 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -43,6 +43,7 @@ show up in /proc/sys/kernel: - hyperv_record_panic_msg - kexec_load_disabled - kptr_restrict +- latencytop - l2cr [ PPC only ] - modprobe ==> Documentation/debugging-modules.txt - modules_disabled @@ -437,6 +438,23 @@ When kptr_restrict is set to (2), kernel pointers printed using ============================================================== +latencytop: + +This value controls whether to start collecting kernel latency +data, it is off (0) by default, and could be switched on (1). +The latency talked here is not the 'traditional' interrupt +latency (which is primarily caused by something else consuming CPU), +but instead, it is the latency an application encounters because +the kernel sleeps on its behalf for various reasons. + +The info is exported via /proc/latency_stats and /proc//latency. + +This file shows up only if CONFIG_LATENCYTOP is enabled, and please +be noted that turning it on may bring notable sytstem overhead when +there are massive scheduling in system. + +============================================================== + l2cr: (PPC only) This flag controls the L2 cache of G3 processor boards. If -- 2.7.4