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=-24.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 2C991C4707F for ; Tue, 25 May 2021 22:17:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03444613FA for ; Tue, 25 May 2021 22:17:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232555AbhEYWTI (ORCPT ); Tue, 25 May 2021 18:19:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232088AbhEYWTG (ORCPT ); Tue, 25 May 2021 18:19:06 -0400 Received: from mail-oi1-x232.google.com (mail-oi1-x232.google.com [IPv6:2607:f8b0:4864:20::232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B827C061574 for ; Tue, 25 May 2021 15:17:35 -0700 (PDT) Received: by mail-oi1-x232.google.com with SMTP id d21so31742831oic.11 for ; Tue, 25 May 2021 15:17:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=rAt0rX4y6MI6ZB6kkQP4Yst97dY399ucmi/u+eK/3GY=; b=CtjGKGpYznf77xLWs1Ue894zcq5aWq12bzNkODUdmqJyvv+cHiAoUUskWgoe9xl/11 j5gT6aIS40ni40dDrTZOZDHg6VQazpry4qrXTrK0HFIhsUbMRYjmW1KPoLGmYYAJiCmN 1J/WAjt9RNxB5C/oBHI3Gjvhkv/IzMV2clwDA1rkz3TRmsKUGi2HZrFyatbwHR+hkIWC 1DrJXBA3q31620hFXQEElNaKOR1vnh5bj99SAhequye3cyItSQKbjaAM+uRfvABcK5Xu 7bw1Dl9UtN1HiPGVHHQJX9ymvrEdFFYRTicmKY9Gw8bxBu1jt4VlimEx3bSfHcwpyVjB OEdg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=rAt0rX4y6MI6ZB6kkQP4Yst97dY399ucmi/u+eK/3GY=; b=eqPEK0BTYedTD4u+NNqX9RhC14O5jA+bG4GRFGf4KypNlPTKWn4HP5sqMicfLSOFYE 62BX5mGpg8l0fvz45X52M6Si9iACg+k1ZxEyeUWqEj2PN2p9RozO/jrqlyGqqKSuwwCL ZRIINF1Zq6J6F9bJ0cMx2+7fBZEOAIPf6GTX3gd8UiBz4NRbWaj8SKDgCMSzntjuhKHy mDeK9XK4HL/sZJR3I1cF7TfLqe4OgmZQ1YTtiF3A8B5wYalGhsHvbJg/co1FVlOC0ZaL L+L3aVLhd6wlFTFzOSJ2FnFiwJfXlMCIrajnS/9LuHJcu+x7L++3FwnR4hAPpUjEsanQ q3Fg== X-Gm-Message-State: AOAM530TOhNSVF3/5+HS9haWCfILxMW+tP6U7W3hRTj3Q3jRwpPZ/e8q hcV357wZGdpGmsUGbAJDgh5gZ1/Gs2FAow== X-Google-Smtp-Source: ABdhPJypwIUtHa2O5+N6hagpKC4xJkrNUf937JJWNQUmUWOjOexUCMZHCDnmWb0SJ+LUVKnTKVMbxg== X-Received: by 2002:aca:1702:: with SMTP id j2mr333254oii.1.1621981054278; Tue, 25 May 2021 15:17:34 -0700 (PDT) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id i26sm3718106oos.21.2021.05.25.15.17.32 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Tue, 25 May 2021 15:17:33 -0700 (PDT) Date: Tue, 25 May 2021 15:17:22 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Peter Zijlstra cc: Hugh Dickins , linux-kernel@vger.kernel.org, rdunlap@infradead.org, joel@joelfernandes.org, Ingo Molnar , juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, Valentin Schneider Subject: Re: [PATCH] sched: Add CONFIG_SCHED_CORE help text In-Reply-To: Message-ID: References: User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 25 May 2021, Peter Zijlstra wrote: > Subject: sched: Add CONFIG_SCHED_CORE help text > From: Peter Zijlstra > Date: Tue May 25 08:53:28 CEST 2021 > > Hugh noted that the SCHED_CORE Kconfig option could do with a help > text. > > Requested-by: Hugh Dickins > Signed-off-by: Peter Zijlstra (Intel) Thanks, Acked-by: Hugh Dickins if necessary (but there's more than enough of me there already). > --- > kernel/Kconfig.preempt | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > --- 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. > +