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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6477AC001DE for ; Fri, 18 Aug 2023 11:19:26 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=djSPoo8X; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4RRzsm5rfdz3cLX for ; Fri, 18 Aug 2023 21:19:24 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=djSPoo8X; dkim-atps=neutral Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4RRzrn08lWz30QQ for ; Fri, 18 Aug 2023 21:18:33 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1692357512; bh=4PjeEkx4aBPMQUwm4BVpDzhj+bdvfmdCom8/6aO1EuQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=djSPoo8XEakClexedz5VHK0XAnbYFl1AB9sSKJR/+v0qiw2S/iJq1YYIGfNyof0Pj AjroU+w+RbY47+XuZ6VPNJHDu4Qzvex5keZ4B1vfkzcynv7YuIkRYub97rSjRF/ZrM fO5EbAZz3DNS1NJOq/EZfZEKYDhJK4md1Empx6ggh+9W1tuu1lkLgnLbu/E3nwJlfc nJUZYadVeJBPrj98Dz8MLr33eFmTks7Vr300gmNZnxCyCq7Mli0Gh95JTTIgqtJSAJ u35yf9Q7RiMn+P3WSEfwFpb3ViL74meGV+Kgs6qQnkGLvtMr3ZEV1UwWto3F6DtE59 Rs9acNe23ublQ== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4RRzrj65skz4wb0; Fri, 18 Aug 2023 21:18:29 +1000 (AEST) From: Michael Ellerman To: Vaibhav Jain , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] powerpc: Enable generic cpu idle-loop In-Reply-To: <20230818050739.827851-1-vaibhav@linux.ibm.com> References: <20230818050739.827851-1-vaibhav@linux.ibm.com> Date: Fri, 18 Aug 2023 21:18:24 +1000 Message-ID: <875y5cwqdb.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain 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: , Cc: "Paul E. McKenney" , Jonathan Corbet , Peter Zijlstra , Catalin Marinas , Randy Dunlap , "Steven Rostedt \(Google\)" , Nicholas Piggin , Vaibhav Jain , Vaidyanathan Srinivasan , Daniel Sneddon Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Vaibhav Jain writes: > This minor patch enables config option GENERIC_IDLE_POLL_SETUP for arch > powerpc. This should add support for kernel param 'nohlt'. Which is named after an 8086 instruction :), but oh well. > Powerpc kernel also supports another kernel boot-time param called > 'powersave' which can also be used to disable all cpu idle-states and > forces CPU to an idle-loop similar to what cpu_idle_poll() does. This > patch however makes powerpc kernel-parameters better aligned to the > generic boot-time parameters. It would be nice if we could make our powersave=off parameter just enable this generic logic. Have you looked at if that's possible? At a glance it looks like it should be, when cpu_idle_force_poll is true do_idle() never calls cpuidle_idle_call(), so the cpuidle drivers are never invoked. cheers