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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 956FEC433E0 for ; Tue, 22 Dec 2020 03:30:37 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C32C622B2D for ; Tue, 22 Dec 2020 03:30:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C32C622B2D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4D0ML14z3TzDqR7 for ; Tue, 22 Dec 2020 14:30:33 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::531; helo=mail-pg1-x531.google.com; envelope-from=npiggin@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=AFT2g43Y; dkim-atps=neutral Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4D0MHt6BL3zDqNr for ; Tue, 22 Dec 2020 14:28:42 +1100 (AEDT) Received: by mail-pg1-x531.google.com with SMTP id w5so7538069pgj.3 for ; Mon, 21 Dec 2020 19:28:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:references:in-reply-to:mime-version:message-id :content-transfer-encoding; bh=GBE3Mvr9HgeX297h6qW2RBB9m/r95z6g6VUdTz0LYyE=; b=AFT2g43Y8RXestXgRueSQc+wsIn3MYd/mHa6VoeL1klA8So/SVtGIA8PfBT8b3otwO xHSxjuidB4aK5CZZ1EE15BRZV5HIz5KYGNabVlWCNUQ51RrTaVXzoHXiVyku/LCBhnRN XJFc0+5VwSwY2hQeSJWbRCKCOOXSqhRi9jQq/3RTmqN6z4G0W/rFoIcmOlbPuKdvTRon J4GHHU+lR/GZngCOF5Jm15jEaR8reeApaM5v/YSboclqTEOYgqQUTYGq1c2YQYUe2zJC AyBfoQINnQrhGK0IWq1/6YeEUdBewFeZIQQP5n4cG4hyLbF91MzyxMNIXPsKRujc6hBz pVYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=GBE3Mvr9HgeX297h6qW2RBB9m/r95z6g6VUdTz0LYyE=; b=Wz/hIJnA7Ws/MzT+Dnt4Zz1TNlVWQ7WKQORH4mKskFg8qTB9hEYmSAFi1aP2wJkYD9 DOr9Sc2IDjR/VXdgpDC9plnt9MOWf4YL7J5aCKVAawfevwHNJOjtaI5aDKAImnHRJsbK ns+XhUoJvRFaUlasBXxaFMQpoZ47czMotNcTIkxfX0jAmAiM2IIh+RuISMjBXWALNIXx gHuDFmQlRBAKQqmVDq9cPhZqjSO9RkypFbwLUoVZcIs1aJOzdI/imbPzPRRj8emomfyx wYVDGB07elkf8/h9taAyjJp2bHQLcWadiWJoInqH3VXrXe61l1gvNMZ6l5oGYm1dW9sH 4zlg== X-Gm-Message-State: AOAM532SnXsghvi0hJo4Vsl1xleD7yKjiZpLSjMtkBapHt+Ro3+uZSAu l5Kla3q4/ksMWHM0PyVwlnsGNkbDNW4= X-Google-Smtp-Source: ABdhPJw9hkEKYXrHzFl+fguxUSI4Pn1zj8JHCsueBQ0AOQ9m6/v5xb88bTtfk/HP9wVAgxwFZL6vew== X-Received: by 2002:a63:4c4b:: with SMTP id m11mr17776240pgl.20.1608607718584; Mon, 21 Dec 2020 19:28:38 -0800 (PST) Received: from localhost (193-116-97-30.tpgi.com.au. [193.116.97.30]) by smtp.gmail.com with ESMTPSA id b13sm18724322pfi.162.2020.12.21.19.28.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Dec 2020 19:28:37 -0800 (PST) Date: Tue, 22 Dec 2020 13:28:32 +1000 From: Nicholas Piggin Subject: Re: [PATCH] powerpc: always enable queued spinlocks for 64s, disable for others To: Christophe Leroy , linuxppc-dev@lists.ozlabs.org References: <20201221032226.888758-1-npiggin@gmail.com> <769ec5dd-8e74-56cb-a3fe-3b657bb3d14c@csgroup.eu> In-Reply-To: <769ec5dd-8e74-56cb-a3fe-3b657bb3d14c@csgroup.eu> MIME-Version: 1.0 Message-Id: <1608607516.sjv8dzuw4m.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Excerpts from Christophe Leroy's message of December 21, 2020 4:04 pm: >=20 >=20 > Le 21/12/2020 =C3=A0 04:22, Nicholas Piggin a =C3=A9crit=C2=A0: >> Queued spinlocks have shown to have good performance and fairness >> properties even on smaller (2 socket) POWER systems. This selects >> them automatically for 64s. For other platforms they are de-selected, >> the standard spinlock is far simpler and smaller code, and single >> chips with a handful of cores is unlikely to show any improvement. >>=20 >> CONFIG_EXPERT still allows this to be changed, e.g., to help debug >> performance or correctness issues. >>=20 >> Signed-off-by: Nicholas Piggin >> --- >> arch/powerpc/Kconfig | 8 +++----- >> 1 file changed, 3 insertions(+), 5 deletions(-) >>=20 >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >> index ae7391627054..1f9f9e64d638 100644 >> --- a/arch/powerpc/Kconfig >> +++ b/arch/powerpc/Kconfig >> @@ -255,6 +255,7 @@ config PPC >> select PCI_MSI_ARCH_FALLBACKS if PCI_MSI >> select PCI_SYSCALL if PCI >> select PPC_DAWR if PPC64 >> + select PPC_QUEUED_SPINLOCKS if !EXPERT && PPC_BOOK3S_64 && SMP >=20 > The condition is a bit complicated, and it doesn't set it to Y by default= when EXPERT is selected. Yeah, I don't know how to do that (switch people's oldconfig from =3DN to=20 =3DY) otherwise (without renaming the option). I think it's enough though,=20 experts should have said yes already :) >=20 >> select RTC_LIB >> select SPARSE_IRQ >> select SYSCTL_EXCEPTION_TRACE >> @@ -506,16 +507,13 @@ config HOTPLUG_CPU >> config PPC_QUEUED_SPINLOCKS >> bool "Queued spinlocks" >> depends on SMP >> + depends on EXPERT || PPC_BOOK3S_64 >> + >=20 > I would do: >=20 > config PPC_QUEUED_SPINLOCKS > bool "Queued spinlocks" if EXPERT > depends on SMP > default PPC_BOOK3S_64 That's nicer. Thanks, Nick