From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 DB6932D2385; Fri, 20 Mar 2026 15:40:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774021238; cv=none; b=T36BAHghY2e0L65XZB0i4L4+/Yyo3jgzEe7n58L99M8dn6VmO+39Nj2DNZZLFuLIYKz6nnKi7eOg7reOMxM3U8lHxabYusALyR+5l7n8YEUjS3dDcozM2fzr0cVi/0M6C4l0J3RwnRPraaZzE8OuC7aGaz0osWBR1Bj7M+jbmg0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774021238; c=relaxed/simple; bh=WfMkJJoh1TlKyO2oBXrzNwS0iCPeE83fkmbgpsSWpGM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rrwcE5ccadcKRUstZTBb+V8ZHCp3S2NYvMUAt/t3mFJsrWV/gxAA1Io7qNqV3UwtRAkrqjUqWpQsTpx1ozR/Hcdh0ulGuD1naNg8mVZB+jrMa4OImycxb/vBTVLkA4V+KO0bd1Z0L1jOFbVG5sJp+igwspNyen4471UGOCpYdls= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=dLkvpinC; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="dLkvpinC" Received: from pps.filterd (m0356517.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 62KEn0ix625531; Fri, 20 Mar 2026 15:40:27 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=3QesG/ 26dNum2Fl13XqhGqFYAzMajIlnjU6g76bS2gM=; b=dLkvpinClBcW9lTJreJrgO 76auraGYN/1yvsFZt4H93uu2pDQvX7CWpO+HX2P5efpU3oe5U9Bkn2AOTm1VrpXw Gv7VCWMplVBfjcWBv/LRrlullGLWA6kd9rsfOwUcx6lCQk4gCIwb5zKI6GhWj7qI 5OJ5EJxs6KU0LrlGUoNrPezI4W+zUu2Yz5ONbfnJ8tspkrPB0wIa2eW0kpsJ+4jf MD3ON6/nHcA2ylv60fzssqAbdxOCu1PvOrJtkxGYUEXhIk4N+xnJSqQXvlpV7fJP A/OmbrSoXELwFQnudI07BZwdX6W4vDGwL6Bao235vmaP7OBBdCSOREme+F7HInOg == Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4cx7vfxh4t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2026 15:40:27 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 62KBQG5h004581; Fri, 20 Mar 2026 15:40:26 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4cwj0sqvg6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 20 Mar 2026 15:40:26 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 62KFeODE11469272 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 20 Mar 2026 15:40:24 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 944F320040; Fri, 20 Mar 2026 15:40:24 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 431CE20043; Fri, 20 Mar 2026 15:40:23 +0000 (GMT) Received: from [9.39.23.72] (unknown [9.39.23.72]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 20 Mar 2026 15:40:23 +0000 (GMT) Message-ID: <7039900f-d598-49af-83c4-42bdb3560238@linux.ibm.com> Date: Fri, 20 Mar 2026 21:10:22 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [tip: sched/hrtick] sched/eevdf: Fix HRTICK duration To: Peter Zijlstra Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Juri Lelli , x86@kernel.org, linux-tip-commits@vger.kernel.org References: <20260224163428.798198874@kernel.org> <177229302335.1647592.2614799712513216333.tip-bot2@tip-bot2> <2fcb640d-a7b7-43dd-b057-50d90d4ca0db@linux.ibm.com> <20260320153823.GN2872@noisy.programming.kicks-ass.net> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <20260320153823.GN2872@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: UHdhIOPivyJxMTLjL_0LLXaOqtOwEGVB X-Authority-Analysis: v=2.4 cv=KajfcAYD c=1 sm=1 tr=0 ts=69bd6a6b cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=mfIysCFPbOgddDM2QVgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzIwMDEyMiBTYWx0ZWRfX9kbtZo8WbG2u xVn4WH3RBGsADZJOgRlh/ljLKKjN+Iqn2lUuboRV5OxPOtB61Q1tmNnHm6amj6BSTmNnYRVqmVP kHXSOep9OcrYzAWNdbsCZLdemGA1RCFDYVCboNqXfUS+NkZPXQE6yvZ0f5dZjMmCkDtAT+j/R9x sxVob4bMKv3YnZIs6MXkvTlq6jM6iDMwA/otxZjW3AqxUmkWefnMIEo81a9e7dgeOoTB3UDZ8KL 0cWApXNEF1MFAJLefDiWUaFs5+BD6XSfYL4vEJeUrznBWqeEbCtBwwTsoc3Ft/HeTAtR2/jv0dx JEmsmN6uR18hRYpAn97WBa3LdMoDXxRzNkOsHAjYRGyzyimDDvsqJQVliEY/uFB586KDSrYyEZk pyjaXh8FmAKoNV48jxA+eXZgP59NhB+BeyVn1lFh2doDhoqTel+QZZF5D2ZIX7Eo05rf+GwqN85 buvMULg3c09T4LZAIyQ== X-Proofpoint-GUID: UHdhIOPivyJxMTLjL_0LLXaOqtOwEGVB X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-20_02,2026-03-20_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 clxscore=1015 impostorscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603200122 On 3/20/26 9:08 PM, Peter Zijlstra wrote: > 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? Yes. That helps.