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Thu, 6 Mar 2025 05:30:10 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AF3B020049; Thu, 6 Mar 2025 05:30:10 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 67CA620040; Thu, 6 Mar 2025 05:30:08 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.in.ibm.com (unknown [9.109.215.252]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 6 Mar 2025 05:30:08 +0000 (GMT) From: Shrikanth Hegde To: juri.lelli@redhat.com, linux-kernel@vger.kernel.org Cc: sshegde@linux.ibm.com, mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, hbathini@linux.ibm.com, joelagnelf@nvidia.com Subject: [PATCH 0/2] sched: issues with sched_rt_runtime_us Date: Thu, 6 Mar 2025 10:59:52 +0530 Message-ID: <20250306052954.452005-1-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.43.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: PvhSCKz2Iij-PW_a8eNd2limQhuRhSkI X-Proofpoint-GUID: -H2MLXdsjrZFQl5WjNBqln_LoxghWUE3 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-06_02,2025-03-05_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 malwarescore=0 phishscore=0 spamscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=980 bulkscore=0 impostorscore=0 priorityscore=1501 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2503060038 ftrace selftest reported below failure in one of the systems. [5] Test tracefs GID mount option [FAIL] On inspection this happens since writing -1 to sched_rt_runtime_us fails. This happened because the possible cpus were more than the active cpus. Fix this issue by considering only the online CPUs for validating the deadline entities. This is minimal impact compared to changing the dl_bw_cpus use possible mask. If that is better, we can follow that approach. There is also another issue that is observed when working on it. Writing any value less than 5% of period results in -EBUSY. This happens since fair_server dl_server allocates 5% of the bandwidth and that is part of the bandwidth of the root domain. Lets document that behaviour since the file allows writing -1 as the minimum. Shrikanth Hegde (2): sched/deadline: use online cpus for validating runtime sched/rt: update limit of sched_rt sysctl in documentation Documentation/scheduler/sched-rt-group.rst | 3 +++ kernel/sched/deadline.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) -- 2.39.3