From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 26CD92E613D for ; Thu, 14 Aug 2025 09:18:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755163103; cv=none; b=bdSSAnzvFyM8cpnRtW2NKtKYmoRNIOrCqysL86UINxD8ZYlTg/IGoIZOsPHoGxTICMtKUVb5LaPOVT9IBGz11ebk8JUxOEDIftQuk8dkPW+azhmK22PCDsTzyAhaShCIvSnviQ3eUmjYAVlXV02JP8/0EnYX6thezjyfgncU070= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755163103; c=relaxed/simple; bh=9jfsBBqeJOEl9hddqXnvpXQHYPzROEJTWzYp929WPI0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KTPSiEt43iO/Z4XDIzbPoRvl/voM14B1TL37AXFWrH5/qoRY8NH+I6zk/fvhMh+1xrh5sFug+kQSXnjsA73MSpCMU2DnsDgaI3++6WgQE6K8BtEaLl1ClHhHlg5S1yN7SSU9jtKm+IyqjNLko/ffUCPKwWR/phsWaBNvsfp4j2Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=RhcIV5ZA; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RhcIV5ZA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755163100; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7KJnGM2svr7YW4cpJgDglh0IED9NSFfVKuR4V+h5zek=; b=RhcIV5ZA4obAKJb3JxOKbN8K4S1LxWLEo/4XV/+viPfjg4SBDzlEV4lIPq3ctE2twxeOW+ vsewoOgIqPhKK2IVpEzu7rs8jlik7c7TSmH2arfo95u4L9N65jYUYYiOd131ryiD4yyL9i EbUFB1U3MZ+fsz4V26VsdJWXhMG7594= Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-504-RC_AcYDiPlaMPQIqdWvKqA-1; Thu, 14 Aug 2025 05:18:18 -0400 X-MC-Unique: RC_AcYDiPlaMPQIqdWvKqA-1 X-Mimecast-MFC-AGG-ID: RC_AcYDiPlaMPQIqdWvKqA_1755163098 Received: by mail-qk1-f200.google.com with SMTP id af79cd13be357-7e870317642so171763985a.0 for ; Thu, 14 Aug 2025 02:18:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755163098; x=1755767898; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7KJnGM2svr7YW4cpJgDglh0IED9NSFfVKuR4V+h5zek=; b=NgLJRYsJpoJwApYRoiSykEFzrAvrL2gapZaOJAkyzFizsHt7gkz05J4gY4rMY+tXA1 tK37Gg+okgbq5/FuQtbx8MC54nBSk7uKgnPywXYnzcJ3ns6GYhFy+qxIPaJiVk28/ZCs p2uptWBnsRVAlXFfsayfnVvqGwkWOFU1vFFS52ytasogc5Kwlfp+UQmZpe/0vVFhlVW0 AQuMk9TrUwVBR3jWNkmtlzncKKF8SHnqyPpkWJeo6gm28pK+Gl70dCRXDIIBSzAASwio QFLdTvVGjwH8JbJ0UB50LuIt0WaK42JXEdwxM+WyvQNaoIJnjFf57Wl4k0slcIoiJqPK dX7g== X-Forwarded-Encrypted: i=1; AJvYcCU4sgyf1hKhQyhU6yipt0b9cAPOaxXsqVnPy4Rp9vrY+AnqVHsSDaQJjEPXzH4Q6UwmUt+d1iE=@vger.kernel.org X-Gm-Message-State: AOJu0YzYTAGAxxm3in+VEB1jDqQ0HAchs+aYzH1NpS5hIRPQU2A6u86i GVByOk/47pwc3TnJ5yv2cdmfzKN8woQGKe9hGyKvI2janpvvUo+LJEu+uZSVhCU3vhlls6OWOVh 61tRdjf/HQ17hjdUU1Dy4QjGz5uWZtM8wymOW7gmvHvH8MpKFqeASmkXvDw== X-Gm-Gg: ASbGncviOusRD2eU9xKGCqiUHEhQdF7xm4peu/BuqhaV4SHKo1geD7URKd77pzG7x7U xjonxUcwlksxek+V03Ezjth9AEnz8bVdkKUARwKsV+ttQYMXHGGYY0ZjtV7kI/vHsEDeSBx2oeG pDfGE2QAQ6IZK9R7RB8mh22/WBEJlSz08ljRBLXNXGXqRT/nqjGpP7+mxH9IOw97augiXoHGbxq 71m3rSCpq33lWyEfruNbvbNaVnj5uQH719GuaillMlY10rQyXJrHXi+lyJft8Ccr8D6KLQqNpIb lNSEpDM2n2g1Hy2qpvF00X4cYavQYxCu+yG4Pdow7AKcAPgHuT+9hMZNt/fwwNOrA0Kc X-Received: by 2002:a05:620a:4009:b0:7e8:710d:a514 with SMTP id af79cd13be357-7e871b61fd6mr232211085a.53.1755163097771; Thu, 14 Aug 2025 02:18:17 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE/rNDxfUSF41mvaZG3MitrVFYLyJLI3VztVogKFuFPmYJr+uIbJGy5RLElJh3Ry5C/7l4gNg== X-Received: by 2002:a05:620a:4009:b0:7e8:710d:a514 with SMTP id af79cd13be357-7e871b61fd6mr232208885a.53.1755163097411; Thu, 14 Aug 2025 02:18:17 -0700 (PDT) Received: from jlelli-thinkpadt14gen4.remote.csb ([151.57.34.72]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7e81bc7a1e3sm1302247985a.74.2025.08.14.02.18.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Aug 2025 02:18:15 -0700 (PDT) Date: Thu, 14 Aug 2025 11:18:10 +0200 From: Juri Lelli To: Jiri Slaby Cc: Greg Kroah-Hartman , stable@vger.kernel.org, patches@lists.linux.dev, Chris Mason , "Peter Zijlstra (Intel)" , Sasha Levin Subject: Re: [PATCH 6.16 199/627] sched/deadline: Less agressive dl_server handling Message-ID: References: <20250812173419.303046420@linuxfoundation.org> <20250812173426.853672780@linuxfoundation.org> <17955c87-1a82-4eae-94ee-3ac1447d4e71@kernel.org> <58c46200-95b0-4cd8-bb5e-44f963a66875@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <58c46200-95b0-4cd8-bb5e-44f963a66875@kernel.org> Hi, On 14/08/25 10:37, Jiri Slaby wrote: > On 14. 08. 25, 10:22, Jiri Slaby wrote: > > Hi, > > > > > > On 12. 08. 25, 19:28, Greg Kroah-Hartman wrote: > > > 6.16-stable review patch.  If anyone has any objections, please let > > > me know. > > > > > > ------------------ > > > > > > From: Peter Zijlstra > > > > > > [ Upstream commit cccb45d7c4295bbfeba616582d0249f2d21e6df5 ] > > > > > > Chris reported that commit 5f6bd380c7bd ("sched/rt: Remove default > > > bandwidth control") caused a significant dip in his favourite > > > benchmark of the day. Simply disabling dl_server cured things. > > > > > > His workload hammers the 0->1, 1->0 transitions, and the > > > dl_server_{start,stop}() overhead kills it -- fairly obviously a bad > > > idea in hind sight and all that. > > > > > > Change things around to only disable the dl_server when there has not > > > been a fair task around for a whole period. Since the default period > > > is 1 second, this ensures the benchmark never trips this, overhead > > > gone. > > > > This causes: > > sched: DL replenish lagged too much > > > > Maybe some prereq missing? > > Not really, this is present both in linus/master and tip/master. https://lore.kernel.org/lkml/20250615131129.954975-1-kuyo.chang@mediatek.com/ should be addressing it, but still under review. Thanks, Juri