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 91EFA54769; Thu, 9 Jan 2025 14:54:13 +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=1736434455; cv=none; b=cZPf251XQVv0WqBgkNiai+6oWbUy3lZMQmlHT3PWdbtIjlyjLtVkhZyaHGztNKcBACr1xDF5rvho8fKMtjJG7vgtquRp59oz+cmplHJQ1BnZVyPIzoug6rhmTyIPYKmfBWim65EnVumAob+5SL4vyXj8oFX5+afzPE42R6KW3og= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736434455; c=relaxed/simple; bh=jgtJZEeueWmBgS7x0jYrg1wO/yLtnQ3r969neK03UPc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kPtbgBXDCRpBQPnzKuy42JWZYbadpjU27ixe9VvgVGgOz2mBlQw2htchC3YiLv2C4KKTjr9M6sU6+Ll03+vFRk7ovq3uGqUjgese1MXQD51AiKOzF6V7dC9ijxYNO1FXRy/TAMhbERAkAjSpCo5kvUXsJYEbX7f68f9jju/MozE= 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=ERKuAusP; 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="ERKuAusP" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=kQlSSzzzFuf3vHaM/p+LVncrUKn7UvEMPTm7/h2S2y0=; b=ERKuAusP7/KxmVRj9Vs7IT/uxZ 7EcFVOWgE6pNRuZf0qEaoW7Qc6Q3QPiNBzReXSWeV04O0VHrW4GQJIdZd+xWEjfP5qSMUmda9EcJz NpK6onkfR7fOHXJTrwGwAgB0/WHl5OKsJcg9celtxyInnXNMQODQVMUanBIat4PLULPLOBouawdMM 7xjWRTXxJqp7zFs8hhfgxwIpZbwioShTotKaYdL5LEZ5AtG4yxMSUDi6k/ywB1RVhMMX/OVrnE57L pCUlg8GRSl0If3LOwiADp5nT72H5O1S1DC4eCi7bQBiHynf2g8xTQ3kEJLigRp384joklI1Jgekt/ AhbybhdA==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tVtvE-00000006Uw4-470J; Thu, 09 Jan 2025 14:54:09 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 974333003AF; Thu, 9 Jan 2025 15:54:08 +0100 (CET) Date: Thu, 9 Jan 2025 15:54:08 +0100 From: Peter Zijlstra To: Sebastian Andrzej Siewior Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Ben Segall , Catalin Marinas , Dietmar Eggemann , Ingo Molnar , Juri Lelli , Mel Gorman , Thomas Gleixner , Valentin Schneider , Vincent Guittot , Will Deacon , x86@kernel.org Subject: Re: [RFC PATCH] preempt: Add a generic function to return the preemption string. Message-ID: <20250109145408.GB5388@noisy.programming.kicks-ass.net> References: <20241206113431.Q-VXMlru@linutronix.de> <20250109114339.GB2981@noisy.programming.kicks-ass.net> <20250109093702.5fe3400d@gandalf.local.home> <20250109143701.GA5388@noisy.programming.kicks-ass.net> <20250109144124.a7MWASit@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250109144124.a7MWASit@linutronix.de> On Thu, Jan 09, 2025 at 03:41:24PM +0100, Sebastian Andrzej Siewior wrote: > On 2025-01-09 15:37:01 [+0100], Peter Zijlstra wrote: > > Upgrade brain. Also the proposed thing was just plain wrong. > > Was it? Yes, things like: > + if (preempt_model_voluntary()) > + return "VOLUNTARY+LAZY"; > + if (preempt_model_none()) > + return "NONE+LAZY"; don't exist and make no sense. > For the !DYNAMIC case everything should be optimized away except > for the current case. > Let me try your thing to see what is different… For the various cases it was supposed to print something like so: RT+DYN: PREEMPT_{RT,(dyn_mode)} RT+LAZY: PREEMPT_{RT,LAZY} RT+FULL: PREEMPT_RT DYN: PREEMPT_(dyn_mode) FULL: PREEMPT LAZY: PREEMPT_LAZY VOLUNTARY: VOLUNTARY NONE: NONE