From nobody Sat Feb 7 06:21:23 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 90E817E9; Thu, 6 Mar 2025 10:02:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741255369; cv=none; b=JT6nlv560mQ5oPoOvWM1lKtMShgrRs0SYf96xWrXRHsEZbBMgbkw/jA7aTZH+q0bt0SIHCoFDKKnc0ia4xU8bZFhI9yMYVfr7mKSivDlRsK/ASLHXls16/geHZYqxIQ+iUXZro8KCqI5RdBQFsa9U07kE5HDuTA7S6Bm8inuPD8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741255369; c=relaxed/simple; bh=OAZkdZE40/RK0vqmcq/gMyMNTym8wcfE31sks6j2O4s=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=HkbWq+CyzyBj6qBf6hQuZX+1FSSa2O+4bezwxXxYRfm7X4nhNU0LiT02Jt9JXPUO3TTLklwACHbi4knKlcUDSV6ZwOtC4Ii0+/m5+0+GHK/eZlrVaU/5hVg2J0qMnDFtQ/4iRbFiBpzM1Lg6em8dOPA6xRBO5nJvc7qUGDaZbP8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=A2Pt+qUq; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=HJ7DtnuC; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="A2Pt+qUq"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="HJ7DtnuC" Date: Thu, 06 Mar 2025 10:02:42 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1741255365; h=from:from:sender:sender:reply-to: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=Ov/RgVd8BFaTCc1hKcQOXWF/eM4LTkT6SJ9nWenpqbk=; b=A2Pt+qUqGGoVZtN5wUKBjdui4yVSHkO1qcP97irJ4x3srAKkl5ONYGWo8qIeDuaoSO3GtQ 1vV9D79QTj+bRSzCiZARLKuDV4CqJlBBa8UNANygpi++otelFGtIjvOr5Jm+lvW1eP+8Po VgEipL7h5ONHyC8cljg0s1dWdnYNpJce4VkaWRVdEooQ2SfW6U18fBb+Iv06qn5ff3c6Cl YOjABAuE8baevo1hnmpjGyutb8vzL8K9+cLt2vtLuDc6G4hBusy3tl7yFGC2Tc+qP7ppd2 8yEX94IKf4Q+B4BYsOSXmEWWb7rrQfz2q9JrIjOzcfiDEm+K8fe8ZofJrNNxlA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1741255365; h=from:from:sender:sender:reply-to: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=Ov/RgVd8BFaTCc1hKcQOXWF/eM4LTkT6SJ9nWenpqbk=; b=HJ7DtnuCuPci4mU+xVXRkA3gAcWW6iSzFR5XL5p241vcWKzEnpFrapox1z70pqDOf40rTV JLHoGbjMnwtOjFDg== From: "tip-bot2 for Shrikanth Hegde" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/urgent] sched/rt: Update limit of sched_rt sysctl in documentation Cc: Shrikanth Hegde , Ingo Molnar , Juri Lelli , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20250306052954.452005-3-sshegde@linux.ibm.com> References: <20250306052954.452005-3-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <174125536231.14745.5392833736932300438.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/urgent branch of tip: Commit-ID: b1536481c81fb604074da799e4f2d2038a1663f7 Gitweb: https://git.kernel.org/tip/b1536481c81fb604074da799e4f2d2038= a1663f7 Author: Shrikanth Hegde AuthorDate: Thu, 06 Mar 2025 10:59:54 +05:30 Committer: Ingo Molnar CommitterDate: Thu, 06 Mar 2025 10:21:31 +01:00 sched/rt: Update limit of sched_rt sysctl in documentation By default fair_server dl_server allocates 5% of the bandwidth to the root domain. Due to this writing any value less than 5% fails due to -EBUSY: $ cat /proc/sys/kernel/sched_rt_period_us 1000000 $ echo 49999 > /proc/sys/kernel/sched_rt_runtime_us -bash: echo: write error: Device or resource busy $ echo 50000 > /proc/sys/kernel/sched_rt_runtime_us $ Since the sched_rt_runtime_us allows -1 as the minimum, put this restriction in the documentation. One should check average of runtime/period in /sys/kernel/debug/sched/fair_server/cpuX/* for exact value. Signed-off-by: Shrikanth Hegde Signed-off-by: Ingo Molnar Reviewed-by: Juri Lelli Link: https://lore.kernel.org/r/20250306052954.452005-3-sshegde@linux.ibm.c= om --- Documentation/scheduler/sched-rt-group.rst | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/sch= eduler/sched-rt-group.rst index 80b05a3..ab46433 100644 --- a/Documentation/scheduler/sched-rt-group.rst +++ b/Documentation/scheduler/sched-rt-group.rst @@ -102,6 +102,9 @@ The system wide settings are configured under the /proc= virtual file system: * sched_rt_period_us takes values from 1 to INT_MAX. * sched_rt_runtime_us takes values from -1 to sched_rt_period_us. * A run time of -1 specifies runtime =3D=3D period, ie. no limit. + * sched_rt_runtime_us/sched_rt_period_us > 0.05 inorder to preserve + bandwidth for fair dl_server. For accurate value check average of + runtime/period in /sys/kernel/debug/sched/fair_server/cpuX/ =20 =20 2.2 Default behaviour