From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A63951F8931; Thu, 14 Nov 2024 11:58:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731585519; cv=none; b=fmEDIlrxDne4CzDPPWldAjpOUs2jotmRgpUUAFFLG6Ptp4zpHpVi3M6PeldsGENQZWvdMS3HGqiR3aN6T8w7+RF6Uf3KmKqvrSH/LBayUfyfiVvtTkvMCfIZV4YUHUF3RdazPhHAQ0LK1rVxUZPBTzkzANFBm8F5Bl+cqKzsg/s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731585519; c=relaxed/simple; bh=opbrCb2+/EFIFD1/+ST5yY9PAJrHhAjniteJAzszCS8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mjMyoFtPXEqFfClYMyJhlo+GQL3SRMNv/TYFD49LXfWxmhVSAurOu7Jx7ZbC//QlBBocOOv1O+Pfq7sFRenSnBg79zfZ05WfFX5kAVQxTbqhwvu4VLAHEYsoix1iwPcYVbyh7v+SudqIucmSWcowLN+PVJ+PEqeFONDaAqY7mGs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mtOgP2S0; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mtOgP2S0" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=4kaHGJ5S7sZTzNrqIdngW3WAgdJKt+QVgXkqBlwP7j8=; b=mtOgP2S0lpX130zqNUPnPIrcfo nFA7r6l3WhBBD2baemhkaUw7KwGsQYTqG1UvmelOqtsZFQC48GUZSDpZk332CdzkTUsRV/2taUZRN dadoU/gfs1DPBeaK6T8klVovyRJtTYQtQFKBI9EyXlzcnlI9Gs53jcYBORV8l4BQhI9DSQbKvqIZc ewgW4q+Y0jlTykLi1foUHeSjIxrukVnmv8hqcUdp5bpoL15r5KG8GcPo7vTBIIx3RLIUiuq3ejgdA 7hTYOncthUisi+4LUDiuW2KLWLa0BEgYO7aufCnadHxTz/ie4KjGcpL7kq3DB0+Cw86jAO+lhmwDF ZK6EzoyQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tBYUa-00000000gVY-1c7W; Thu, 14 Nov 2024 11:58:32 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 08B30300472; Thu, 14 Nov 2024 12:58:32 +0100 (CET) Date: Thu, 14 Nov 2024 12:58:31 +0100 From: Peter Zijlstra To: "Gautham R. Shenoy" Cc: "Rafael J. Wysocki" , Patryk Wlazlyn , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael.j.wysocki@intel.com, len.brown@intel.com, artem.bityutskiy@linux.intel.com, dave.hansen@linux.intel.com Subject: Re: [PATCH v3 2/3] x86/smp native_play_dead: Prefer cpuidle_play_dead() over mwait_play_dead() Message-ID: <20241114115831.GQ6497@noisy.programming.kicks-ass.net> References: <20241108122909.763663-1-patryk.wlazlyn@linux.intel.com> <20241108122909.763663-3-patryk.wlazlyn@linux.intel.com> <20241112114743.GQ22801@noisy.programming.kicks-ass.net> <20241112145618.GR22801@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Nov 13, 2024 at 05:11:38PM +0530, Gautham R. Shenoy wrote: > AMD platforms won't be using FFH based states for offlined CPUs. We > prefer IO based states when available, and HLT otherwise. > > > > > Robustly we'd teach the ACPI driver about FFh and set enter_dead on > > every state -- but we'd have to double check that with AMD. > > Works for us as long as those FFh states aren't used for play_dead on > AMD platforms. AFAIU AMD doesn't want to use MWAIT -- ever, not only for offline. Confirm? But if it were to use MWAIT for regular idle, then surely it's OK for offline too, right?