[PATCH v3 0/1] Fix lb_imbalance reporting in /proc/schedstat

From: Swapnil Sapkal
Date: Mon Mar 18 2024 - 05:25:36 EST


This patch adds new fields to /proc/schdstat. First version of
the patch is sent here [1]. This patch goes on top of the
commit d72cf62438d6 ("sched/balancing: Fix a couple of outdated function names in comments")
from tip/sched/core. This change is intended to be a part of v16 of
/proc/schedstat.

v2 --> v3 change:
- Incorporated review comment by Shrikanth Hegde
- Added reviewed by.

v1 --> v2 change:
- Added links to previous schedstat documentation
- Incorporated review comments by Shrikanth Hegde

Motivation:

In /proc/schedstat, lb_imbalance reports the sum of imbalances
discovered in sched domains with each call to sched_balance_rq(), which is
not very useful because lb_imbalance does not mention whether the imbalance
is due to load, utilization, nr_tasks or misfit_tasks. Remove this field
from /proc/schedstat.

Currently there is no field in /proc/schedstat to report different types
of imbalances. Introduce new fields in /proc/schedstat to report the
total imbalances in load, utilization, nr_tasks or misfit_tasks.

[1] https://lore.kernel.org/lkml/66f1e42c-9035-4f9b-8c77-976ab50638bd@xxxxxxx/

Swapnil Sapkal (1):
sched: Report the different kinds of imbalances in /proc/schedstat

Documentation/scheduler/sched-stats.rst | 121 ++++++++++++++----------
include/linux/sched/topology.h | 5 +-
kernel/sched/fair.c | 21 +++-
kernel/sched/stats.c | 7 +-
4 files changed, 99 insertions(+), 55 deletions(-)

--
2.34.1