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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,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 2D64CC4708F for ; Tue, 1 Jun 2021 14:05:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0616D61376 for ; Tue, 1 Jun 2021 14:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234370AbhFAOHB (ORCPT ); Tue, 1 Jun 2021 10:07:01 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:33174 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234206AbhFAOGk (ORCPT ); Tue, 1 Jun 2021 10:06:40 -0400 Date: Tue, 01 Jun 2021 14:04:57 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1622556298; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rYC9ZduJnAjuxjdLWAeAQnaSva6G2B+jOPkc7wyTFOY=; b=SGc8aCWzbWV1eBXFYkbzxj55GJIDuoyBJ1TTgScwuwAPoVBxaBDksl9uVfkFxdrjWeP+MQ Av+0bCwPG3t7XBPPF9ysOsOGm7NDycCx21m7xWpM37puU5CBhFhE2Vxw/HikBgyS1evbYT ux0WfC4hv8jK94Zvap8w9BMH1Oj4Ju/uDMCPbDsIOSrJSUjJgOrzpviPC36lZNNOO337gu p1i6/2iOVoRZpSADoM9T6YU4/rGGzsTJhRlpxZpObqG6mNiwG8QZNWc4G9am1iaYRgzVb+ zZPOcX1gOuP6Oh6zmVmmVmSEMOKn+wf2iVWW9H9Fcl3OaT1UU/ZTW+JZGrd5Fg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1622556298; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rYC9ZduJnAjuxjdLWAeAQnaSva6G2B+jOPkc7wyTFOY=; b=YtfrKRWFRSudy2wXh4rU+7Ok5+D2lq9JbJ0OIlV8USAtwmPne3BJurPdswvBoOEdvpMo6o bFx9JLaBlMcFU1DA== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched: Add CONFIG_SCHED_CORE help text Cc: "Peter Zijlstra (Intel)" , Randy Dunlap , Hugh Dickins , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: MIME-Version: 1.0 Message-ID: <162255629757.29796.5663233849330605967.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 7b419f47facd286c6723daca6ad69ec355473f78 Gitweb: https://git.kernel.org/tip/7b419f47facd286c6723daca6ad69ec355473f78 Author: Peter Zijlstra AuthorDate: Tue, 25 May 2021 08:53:28 +02:00 Committer: Peter Zijlstra CommitterDate: Tue, 01 Jun 2021 16:00:10 +02:00 sched: Add CONFIG_SCHED_CORE help text Hugh noted that the SCHED_CORE Kconfig option could do with a help text. Requested-by: Hugh Dickins Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Randy Dunlap Acked-by: Hugh Dickins Link: https://lkml.kernel.org/r/YKyhtwhEgvtUDOyl@hirez.programming.kicks-ass.net --- kernel/Kconfig.preempt | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index ea1e333..bd7c414 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -104,4 +104,18 @@ config SCHED_CORE bool "Core Scheduling for SMT" default y depends on SCHED_SMT + help + This option permits Core Scheduling, a means of coordinated task + selection across SMT siblings. When enabled -- see + prctl(PR_SCHED_CORE) -- task selection ensures that all SMT siblings + will execute a task from the same 'core group', forcing idle when no + matching task is found. + + Use of this feature includes: + - mitigation of some (not all) SMT side channels; + - limiting SMT interference to improve determinism and/or performance. + + SCHED_CORE is default enabled when SCHED_SMT is enabled -- when + unused there should be no impact on performance. +