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Thu, 3 Sep 2026 06:34:05 +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 v12 09/13] sched/debug: Add migration stats due to non preferred CPUs Date: Thu, 3 Sep 2026 12:02:36 +0530 Message-ID: <20260903063240.268775-10-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260903063240.268775-1-sshegde@linux.ibm.com> References: <20260903063240.268775-1-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=EIc2FVZC c=1 sm=1 tr=0 ts=6a9914ec cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=tZLFZcUqokv_Co2pBPUA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTAzMDA1NyBTYWx0ZWRfX8hD5P2BU39Rh aW/WvxEnSa91HNRXC6v1RS1uP1obwE8ywPQGcbvWwBV9Jjj1NPSo9Ivi4tGkyDcgai0d7bO7EII a8Jg9onoLpr9JER9KTlRPmd6ikCxOo8IaGcpPeFMcs+ZxnXoru7+5wipz3t/q/jlPGWmLsUFqWF SQUu6TZIsL90ONIJaBmNux+CluoqkyW8W22lh7DIUXpDYxES5/Hf3TEKFHiWEujWXwn+u42cENs nAtuklG/EWFwXZOwYaAMwZJN0zOfVZcBUaEIktZ+RWA15OaZ3Zue2502+r5tkd6CFvEoi5eCkRO i82fqfiE7cjUr7Sxp/KuJJvVJP+RrBahKIB8biiIzuj4acX1C9DXUWKaSxiLgDioHvI3mHHbjh0 v6ANHJTpQ/zJtOLDpZQdZvVkWM/tYpwoFslANfX6+auCDo+poVzvKWICmrIkFkq0gm/KgmDri5I fhFg3bdGvaERX6Qu39Q== X-Proofpoint-GUID: XgbEPRi2WnUmHjVVaEaOfljsvZEsVPE3 X-Proofpoint-ORIG-GUID: 2vj7drW60NxyzUUQwajx0Bk4wUIvqkAb X-Proofpoint-Spam-Info: AW1haW4tMjYwOTAzMDA1NyBTYWx0ZWRfXxQJ3fqak60Fy J8KeGDvvmN8jwuGTjmKvQwI+9GnX5s4XBBB5NUzLkSBL414qb/ljt6uWVyTXv+smls5ddVWZOm9 xy/M42kbB7NKQhRxLORj1JjubgWYd+o= 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=2026-09-03_02,2026-09-02_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 suspectscore=0 priorityscore=1501 clxscore=1015 phishscore=0 spamscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609030057 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 d7cc77181ef9..48639b0c75d0 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 35e7eedad104..f32e9fc47b68 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -11234,8 +11234,13 @@ 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 fda10b3fa249..e6a3b516c703 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -1440,6 +1440,7 @@ 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); -- 2.52.0