From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 0FC7E3CAE87; Fri, 20 Mar 2026 15:38:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774021113; cv=none; b=A7oBt09M0yg7AwgWRPjF8ukUkyRAfKPwWC0yMpoPXR0smzZDbHPomWHXdFz/KLjnyZMUH8f21h7EIEdUNpUPj//RMhmsJ2Sf6nkMsvbKxd+F5vNLvcO+l9q8Opbr8APV4wQVGTCpWuVXHFiEH0+T/D74dArbyUAyU4Tp5gvIiWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774021113; c=relaxed/simple; bh=z6lF+m0Yr0xJxn40ynw0AapaWvvbZcoAlN9qeuOjfH4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E07TCh8I7NLy8bxoldzX1cB87v33Qtfyo494mXhYQd61Z1+zuxO/YkhYQ7C5FxBwpyqRK2fMiRGX1BPUFRl9dxndFbRuGLYsRLozJSMS251wet7qotGbXXlLyeYZCpthIB5GFK5fwzLEPVUXUrs+Gm7JB2BIaGvswhWpmWr2rU4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=kYrlufGb; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="kYrlufGb" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=ejXnrxSZlMOO7Nnlo9RFSZdIKZB8OsVI9A+2+NFCXEs=; b=kYrlufGbv+17mFbaYlSgOFcUlI 3nrIp57pCNWDHPasaxv22/3PjWh997gqg+/xrNxsHLeYKW3md/TDb6hMd3QVY567h5ivoo+NPMdmx 29a01Smel0ZJj5vnDYhWzmzNhhbmU4YAo3qaJlXndOmPQX3MIcifVcJAIud9MxmVBkhwHLHOLOnmz 9HxnbPmLo1bajAgBzqHGJ4sIFOAbAo+3aMf2O8yKDLVrIZn9XbgNNlqs3UnOc33BcbkGrEk/cvPce Jv3r42+N4RIDKnAVF+3XEfoKWYt9ikgdN407JRpNbiS142TEgYtiSpC0SF8jEIrMzLw4KuaNJmrzx Gv72Mm+A==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w3bvc-0000000Fs8r-0XFW; Fri, 20 Mar 2026 15:38:24 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 3C619303169; Fri, 20 Mar 2026 16:38:23 +0100 (CET) Date: Fri, 20 Mar 2026 16:38:23 +0100 From: Peter Zijlstra To: Shrikanth Hegde Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Juri Lelli , x86@kernel.org, linux-tip-commits@vger.kernel.org Subject: Re: [tip: sched/hrtick] sched/eevdf: Fix HRTICK duration Message-ID: <20260320153823.GN2872@noisy.programming.kicks-ass.net> References: <20260224163428.798198874@kernel.org> <177229302335.1647592.2614799712513216333.tip-bot2@tip-bot2> <2fcb640d-a7b7-43dd-b057-50d90d4ca0db@linux.ibm.com> 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: <2fcb640d-a7b7-43dd-b057-50d90d4ca0db@linux.ibm.com> On Fri, Mar 20, 2026 at 08:29:11PM +0530, Shrikanth Hegde wrote: > > + /* > > + * Correct for instantaneous load of other classes. > > + */ > > + util += cpu_util_irq(rq); > > + if (util && util < 1024) { > > + scale *= 1024; > > + scale /= (1024 - util); > > + } > > Comments/Changelog says other classes. > > Then why not consider cpu_util_dl, cpu_util_rq too? > Is there a reason why these are not taken into calculations? Damn, forgot to fix that comment. So yes, it used to correct for those, but then I realized that the hrtick is strictly for current. So running RT/DL tasks means current is different. The only thing that can actually interrupt current and soak time are interrupts. Does that make sense?