From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from serv15.avernis.de (serv15.avernis.de [176.9.89.163]) (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 A1B0B349CC8 for ; Tue, 12 May 2026 10:28:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=176.9.89.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778581710; cv=none; b=BhwRN1QKWPE2pIJD0Pp8vmJ5XBjYJNPuhKjYVtMcpTZ7i8nSNwbx9hFrtsvAS7jr2p+69YspLMJ/DJgqv6nrn6NrYYxdqCpcoT4Uz+J0ZSsjeLI9k2BZk4gkt2w7lNWwJi5au3xdIisQvXtUASnvMckiXRwZzYHL+S9sHD95IV8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778581710; c=relaxed/simple; bh=rdRAJVmXBZCsVNNRLdnT817dI4PPUvjS9ahqDUpy7Bw=; h=MIME-Version:Date:From:To:Cc:Subject:In-Reply-To:References: Message-ID:Content-Type; b=Cj2zmDc+RCyqJIguTX4s2iaFccpk14pGzQZZsEEKtB/a1IwDtBqIctDyqH7jS4R8yMcnGt6KiUv0Oh7pp9qpfdnnGPU+qWZbdNb/IBUmK+aU/Qqu7hAJfd4znN/MCIzNF2OcwXUGlRecCoR/lfmwi5oGdFGKyw3zsBcYvq7gEnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=umbiko.net; spf=none smtp.mailfrom=umbiko.net; dkim=pass (1024-bit key) header.d=umbiko.net header.i=@umbiko.net header.b=IRY/dWQn; arc=none smtp.client-ip=176.9.89.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=umbiko.net Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=umbiko.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=umbiko.net header.i=@umbiko.net header.b="IRY/dWQn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=umbiko.net; s=mail; t=1778581705; bh=rdRAJVmXBZCsVNNRLdnT817dI4PPUvjS9ahqDUpy7Bw=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=IRY/dWQnQVHEF4DwKcVbGN5hnCzgY8ceRaUzVpI49kN2+/FbHUy3yF7IoGeRmZUku y+ostqcnxHiNlD1cKnqG+Er2Xfv7t5Y59QQgkJItYwmZ44Oab/7xJ/T1idw2NdBJa5 5c7BmIguNJq2PnCYjYDGnFmnKcm4zNX9G3rUdT+M= Received: by serv15.avernis.de (Postfix) with ESMTPSA id 5856DBDE5880; Tue, 12 May 2026 12:28:24 +0200 (CEST) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 12 May 2026 10:28:24 +0000 From: Andreas Ziegler To: Juri Lelli Cc: Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: sched/deadline: Use revised wakeup rule for dl_server In-Reply-To: References: <496e4b3329fe258da9618b9f05b18fcf@umbiko.net> Message-ID: X-Sender: br025@umbiko.net Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 1.4.3 at serv15.avernis.de X-Virus-Status: Clean Hi Juri, Everyone On 2026-05-11 12:46, Juri Lelli wrote: > Hello, > > On 08/05/26 08:09, Andreas Ziegler wrote: >> Linux kernel version: 6.12 >> CONFIG_PREEMPT_RT (w/ PREEMPT_RT patch applied) >> Architecture: aarch64 >> Platform: Raspberry Pi 4 >> >> Hi everyone, >> >> Commit d66792919d4f (sched/deadline: Use revised wakeup rule for >> dl_server) >> [1] introduced a marked degradation in scheduling latency for >> real-time >> tasks in the presence of heavy I/O load. > > Can this be the same regression reported here? > > https://marc.info/?l=linux-rt-users&m=177844667227991 > > Please notice the list of missing subsequent fixes Mike is suggesting > to > test with. > > https://marc.info/?l=linux-rt-users&m=177847863710263&w=2 The patch set works for me so far. cccb45d7c429 ("sched/deadline: Less agressive dl_server handling") (6.17) 4ae8d9aa9f9d ("sched/deadline: Fix dl_server getting stuck") (6.17) a3a70caf7906 ("sched/deadline: Fix dl_server behaviour") (6.17) > Thanks, > Juri Kind regards, Andreas