Messages in this thread | | | From | Chengming Zhou <> | Subject | [PATCH v6 0/9] sched/fair: task load tracking optimization and cleanup | Date | Thu, 18 Aug 2022 20:47:56 +0800 |
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Hi all,
This patch series is optimization and cleanup for task load tracking when task migrate CPU/cgroup or switched_from/to_fair(), based on tip/sched/core.
There are three types of detach/attach_entity_load_avg (except fork and exit) for a fair task: 1. task migrate CPU (on_rq migrate or wake_up migrate) 2. task migrate cgroup (detach and attach) 3. task switched_from/to_fair (detach later attach)
patch 1-3 cleanup the task change cgroup case by remove cpu_cgrp_subsys->fork(), since we already do the same thing in sched_cgroup_fork().
patch 5/9 optimize the task migrate CPU case by combine detach into dequeue.
patch 6/9 fix another detach on unattached task case which has been woken up by try_to_wake_up() but is waiting for actually being woken up by sched_ttwu_pending().
patch 7/9 remove unnecessary limitation that we would fail when change cgroup of forked task which hasn't been woken up by wake_up_new_task().
patch 8-9 optimize post_init_entity_util_avg() for fair task and skip setting util_avg and runnable_avg for !fair task at the fork time.
Thanks!
Changes in v6: - Use TASK_NEW to check new forked task which hasn't been woken up by wake_up_new_task(), suggested by Peter Zijlstra. Thanks! - Update comments related to post_init_entity_util_avg() in patch 8/9.
Changes in v5: - Don't do code movements in patch 6/9, which complicate code review, as suggested by Vincent. Thanks! - Fix a build error of typo in patch 7/9.
Changes in v4: - Drop detach/attach_entity_cfs_rq() refactor patch in the last version. - Move new forked task check to task_change_group_fair().
Changes in v3: - One big change is this series don't freeze PELT sum/avg values to be used as initial values when re-entering fair any more, since these PELT values become much less relevant. - Reorder patches and collect tags from Vincent and Dietmar. Thanks! - Fix detach on unattached task which has been woken up by try_to_wake_up() but is waiting for actually being woken up by sched_ttwu_pending(). - Delete TASK_NEW which limit forked task from changing cgroup. - Don't init util_avg and runnable_avg for !fair taks at fork time.
Changes in v2: - split task se depth maintenance into a separate patch3, suggested by Peter. - reorder patch6-7 before patch8-9, since we need update_load_avg() to do conditional attach/detach to avoid corner cases like twice attach problem.
Chengming Zhou (9): sched/fair: maintain task se depth in set_task_rq() sched/fair: remove redundant cpu_cgrp_subsys->fork() sched/fair: reset sched_avg last_update_time before set_task_rq() sched/fair: update comments in enqueue/dequeue_entity() sched/fair: combine detach into dequeue when migrating task sched/fair: fix another detach on unattached task corner case sched/fair: allow changing cgroup of new forked task sched/fair: move task sched_avg attach to enqueue_task_fair() sched/fair: don't init util/runnable_avg for !fair task
kernel/sched/core.c | 52 ++++--------------- kernel/sched/fair.c | 120 ++++++++++++++++++++----------------------- kernel/sched/sched.h | 6 +-- 3 files changed, 66 insertions(+), 112 deletions(-)
-- 2.37.2
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