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Thu, 25 Jun 2026 12:48:20 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.39.20.6]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 25 Jun 2026 12:48:20 +0000 (GMT) From: Shrikanth Hegde To: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, yury.norov@gmail.com, kprateek.nayak@amd.com, iii@linux.ibm.com, corbet@lwn.net Cc: sshegde@linux.ibm.com, tglx@kernel.org, gregkh@linuxfoundation.org, pbonzini@redhat.com, seanjc@google.com, vschneid@redhat.com, huschle@linux.ibm.com, rostedt@goodmis.org, dietmar.eggemann@arm.com, maddy@linux.ibm.com, srikar@linux.ibm.com, hdanton@sina.com, chleroy@kernel.org, vineeth@bitbyteword.org, frederic@kernel.org, arighi@nvidia.com, pauld@redhat.com, christian.loehle@arm.com, tj@kernel.org, tommaso.cucinotta@gmail.com, maz@kernel.org, rafael@kernel.org, rdunlap@infradead.org, kernellwp@gmail.com, linux-doc@vger.kernel.org Subject: [PATCH v5 10/24] sched/core: Keep tick on non-preferred CPUs until tasks are out Date: Thu, 25 Jun 2026 18:16:34 +0530 Message-ID: <20260625124648.802832-11-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260625124648.802832-1-sshegde@linux.ibm.com> References: <20260625124648.802832-1-sshegde@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=X4Ni7mTe c=1 sm=1 tr=0 ts=6a3d23a1 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=QWx9vYyWXuU5Gb4Iy2kA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjI1MDExMCBTYWx0ZWRfX/JRwtzo8+vRl CO+UzgL99Uv2ToFft1TNmuscdkczB8IjtTOdMqiYPjKz35q0R3ioBW+s2Sni8TwTR9giq+Ehgub d3HAoWASxSSwV6uQKwvY52ISiBrdlOs= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjI1MDExMCBTYWx0ZWRfX2l6dCzUNzcwA 0WlYFIbQyhDM94Rt1lqGxGeqFt/s+BxK0DSdu5aow+PTbYYnvZPHrrNoSQs72RVYZwEYS4ice+l GIKsgWPWEkEmVLX1UNO7OsFhtJcSEk5//n5VwpTxFisKA/iDG92N3SwQ50suiquUbEmPO+L4noi EzHnOXAggOMAy3O85+zBsVwuYqX9n3olrfvmltTXAK5DJbqOp7p8/cLWIcBhI+SBYyEgxbpAWVs AkdHA32rrbDMBVyrvICtktjj3add+dCarz6bDNd1EcdUHRsGtKSZr8HTg8gmKjA7OdV6UQUyDj0 Vp1QIilJwn+XJyfHqsH21uNnguiId5giPZ5KL3hkSFKSps0ovQaLNuDv78FKo4FfZxK2Rp0Bfvm g1o8xlybGIlVYR1pqTTJALn18Q+lZMwYJs05HHEhtP/+gODK1Gn4swbfX7FsGwZWXI0OubF8piL g1v1G5u8BD1GqC7ryWA== X-Proofpoint-ORIG-GUID: r03RhPCW6rwdtxvoZNmu2xilbXUJZxvr X-Proofpoint-GUID: qEJnhaFQSRIJ5Xh5lgpJASRKo-Cf-179 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-25_01,2026-06-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 suspectscore=0 spamscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606250110 Enable tick on nohz full CPU when it is marked as non-preferred. If there in no CFS running there, disable the tick to save the power. Steal time handling code will call tick_nohz_dep_set_cpu with TICK_DEP_BIT_SCHED for moving the task out of nohz_full CPU fast. Signed-off-by: Shrikanth Hegde --- v4->v5: - Move it below rt checks. (Sashiko) kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 281715a6e88f..c0391e7897f5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1473,6 +1473,10 @@ bool sched_can_stop_tick(struct rq *rq) return false; } + /* Keep the tick running until CFS tasks are pushed out*/ + if (!cpu_preferred(rq->cpu) && rq->cfs.h_nr_queued) + return false; + return true; } #endif /* CONFIG_NO_HZ_FULL */ -- 2.47.3