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 E288C4EB869 for ; Tue, 13 Oct 2026 11:31:49 +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=1791891112; cv=none; b=f398C2rhIAksjHMeDv1XJWXM2N1TITdTBxZsVVVyQhG5ZRKdmxwWyDUfPS/8lc+AEon+W8+1tZ4YXkxLWb4GhG7kcPswVG57HfBJoZmb/WgZZYnGZwhE63dvETQHifOWP6jH9mvFXtxog30I0wlwXlGkO0I7i+xpotaU6wXx2EA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791891112; c=relaxed/simple; bh=5MztiLkG8C8Of18/XOCPFRiKCdmJGnwwdtVWbkVo86k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=t5oLA5E50yRg9aSq0N7fN42tJcJSxQnKVK4LyMxXSFGJWk8cuQwSgD13CoBnFnQXRHSFyw1GqmYIrErYqaXd0DW1yzOHokVGRDw3GPaACP6mw6dJTGZwSiJGUMxGXskNAcPACPP08ObA+Z4PZESjjsk5ii6LkZ/4IZdMoSjxb/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=XK3UVSVO; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass 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="XK3UVSVO" 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=5MztiLkG8C8Of18/XOCPFRiKCdmJGnwwdtVWbkVo86k=; b=XK3UVSVOLtyiU9zLSXFBF8AMhC WC1xDLrMWbx46mIpkpe2tWRcKObo/jlrUtQ15rmKd3Z6ROV1CDnhZfWTBMAejTnfdCRanLQt9k9a6 HefUoSYB+BICTATKqG/DBwcI99XmXRnbsaZV4ermfzcveOomRDdMrzLkGcKclRg9uGZ0E0Y6DW3GR QEFLkQ5Zd1kieQx8zvCZM22sDRp110XEL+HfWQaDmWtWR0l65yRyEr6/6uWYw3MnIHiC/upqTQzdR D7QkAj7Y59z567ahbomZbdGgRbe1Lo7fR84vUDDhutbXu9DkCmWI/KAkYS6GyFoafy2I9svwR3/vc FzjxJs7A==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1xGajS-0000000D1T0-0DPd; Tue, 13 Oct 2026 11:31:46 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id F02BE30015F; Tue, 13 Oct 2026 13:31:44 +0200 (CEST) Date: Tue, 13 Oct 2026 13:31:44 +0200 From: Peter Zijlstra To: Chengfeng Lin Cc: Vincent Guittot , Ingo Molnar , Juri Lelli , Dietmar Eggemann , linux-kernel@vger.kernel.org Subject: Re: [RFC] sched/fair: avoid redundant updates for unchanged default slices Message-ID: <20261013113144.GH2009045@noisy.programming.kicks-ass.net> References: <20261012105953.GR4121339@noisy.programming.kicks-ass.net> 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=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 13, 2026 at 05:58:17PM +0800, Chengfeng Lin wrote: > The attached default-slice-peter-v4.patch is the revision tested here, > against unmodified v7.2. Does this look like a reasonable way to keep > the unchanged-parameter fast path while handling these cases? Yes, this looks reasonable.