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Tue, 25 Aug 2026 10:40:37 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.39.21.103]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 25 Aug 2026 10:40:37 +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, meted@linux.ibm.com, ynorov@nvidia.com 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, jgross@suse.com, virtualization@lists.linux.dev, sunlightlinux@gmail.com Subject: [PATCH v11 08/12] sched/debug: Add migration stats due to non preferred CPUs Date: Tue, 25 Aug 2026 16:08:51 +0530 Message-ID: <20260825103855.721013-9-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260825103855.721013-1-sshegde@linux.ibm.com> References: <20260825103855.721013-1-sshegde@linux.ibm.com> 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-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=TfimcxQh c=1 sm=1 tr=0 ts=6a8d7133 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=-i9lZGrASMRMKgkbeRgA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI1MDA4OSBTYWx0ZWRfXzWtzZte3SU6w Kexcw9wuR7eTbaEuNuzMjpbsaq9QLIgMeUearlD6uMUmilDZyi2OF7sCRlEz2XbCEouuuBrkqjB 2TtZEnpJmA251buBik0eAJI/cQ/jTjM= X-Proofpoint-GUID: vp3WLSpTWu8piiDa4fCbp5S59kfnMNKe X-Proofpoint-ORIG-GUID: DWqDtcZY1EYHHP7L3PvT0Di5dI_bQiVA X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI1MDA4OSBTYWx0ZWRfX2Ryqr09CO4ox lMbpsE2TY36GhJ7o7K4x6PoiQ6dRzS+Xxl2ZHiKMxLYkuTSxq7d/zUTZuZWk0Lt8AD4QpQKXQQ+ ZkcoZpV8hmUcOX4gPnKOhkb6BcxtH6sZT/l/YSVEAdC8BP5ACWsl7ZdTAbJpLEQ0nzPafoGcv+8 3i8fr54l0LWRYe5y9cu98yh8P+Q90KuDo9ENRTnwAjp63qkLiD2NrUVus5BwFxEnjTgzFd4Nw0X mFitIzAormBzcp/ec9kuv3CdUXCPvASSL+2QwCgoB9595P9HRB7pBsmhyZXueC4TvyufEl6Zn+l lH38lLJmrc24x1HaPVf+wwXLJYUj2+qIrYSYnEwuN81h1RGZTlXxcCjgXyE/Bq5fFai8taJsaw5 uC7mxt/OW4md3NkE2Y0F+utaYiudlKPsLs7MJ62E4j6VzGGO0+ePOf1p6BDAgJ7JCbkaQzI1VID 8lYl9HBN1v2q1vLCqow== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-25_02,2026-08-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 phishscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608250089 Add a new stat, - nr_migrations_cpu_non_preferred: number of migrations happened since a CPU was marked as non preferred due to high steal time. Signed-off-by: Shrikanth Hegde --- include/linux/sched.h | 1 + kernel/sched/core.c | 9 +++++++-- kernel/sched/debug.c | 1 + 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 968b18a7f470..37849d2f1dbd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -554,6 +554,7 @@ struct sched_statistics { u64 nr_failed_migrations_running; u64 nr_failed_migrations_hot; u64 nr_forced_migrations; + u64 nr_migrations_cpu_non_preferred; u64 nr_wakeups; u64 nr_wakeups_sync; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2521ed5ce576..e73d2dd997b3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -11353,8 +11353,13 @@ static int sched_non_preferred_cpu_push_stop(void *arg) context_unsafe_alias(rq); if (task_rq(p) == rq && task_on_rq_queued(p) && - !is_migration_disabled(p)) - rq = __migrate_task(rq, &rf, p, cpu); + !is_migration_disabled(p)) { + struct rq *dest_rq = __migrate_task(rq, &rf, p, cpu); + + if (rq != dest_rq) + schedstat_inc(p->stats.nr_migrations_cpu_non_preferred); + rq = dest_rq; + } rq_unlock(rq, &rf); raw_spin_unlock_irq(&p->pi_lock); diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 72236db67983..5ebb2055e6d5 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -1446,6 +1446,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, P_SCHEDSTAT(nr_failed_migrations_running); P_SCHEDSTAT(nr_failed_migrations_hot); P_SCHEDSTAT(nr_forced_migrations); + P_SCHEDSTAT(nr_migrations_cpu_non_preferred); P_SCHEDSTAT(nr_wakeups); P_SCHEDSTAT(nr_wakeups_sync); P_SCHEDSTAT(nr_wakeups_migrate); -- 2.47.3