diff options
| author | Srivatsa Vaddagiri <vatsa@codeaurora.org> | 2014-11-18 13:19:39 +0530 |
|---|---|---|
| committer | David Keitel <dkeitel@codeaurora.org> | 2016-03-23 20:01:17 -0700 |
| commit | 29a412dffa5cbd6d7d913909cd57d04d9d5cb172 (patch) | |
| tree | 034ba56d1040d86df67375ab1683e058c521b65b /kernel/sysctl.c | |
| parent | d1b240ccc7317c502b8a051a7d94466de482f8a4 (diff) | |
sched: Avoid frequent migration of running task
Power values for cpus can drop quite considerably when it goes idle.
As a result, the best choice for running a single task in a cluster
can vary quite rapidly. As the task keeps hopping cpus, other cpus go
idle and start being seen as more favorable target for running a task,
leading to task migrating almost every scheduler tick!
Prevent this by keeping track of when a task started running on a cpu
and allowing task migration in tick path (migration_needed()) on
account of energy efficiency reasons only if the task has run
sufficiently long (as determined by sysctl_sched_min_runtime
variable).
Note that currently sysctl_sched_min_runtime setting is considered
only in scheduler_tick()->migration_needed() path and not in
idle_balance() path. In other words, a task could be migrated to
another cpu which did a idle_balance(). This limitation should not
affect high-frequency migrations seen typically (when a single
high-demand task runs on high-performance cpu).
CRs-Fixed: 756570
Change-Id: I96413b7a81b623193c3bbcec6f3fa9dfec367d99
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
[joonwoop@codeaurora.org: fixed conflict in set_task_cpu() and
__schedule().]
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1465fb869657..9c2719cc9cc9 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -373,6 +373,13 @@ static struct ctl_table kern_table[] = { .proc_handler = sched_hmp_proc_update_handler, }, { + .procname = "sched_min_runtime", + .data = &sysctl_sched_min_runtime, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { .procname = "sched_spill_load", .data = &sysctl_sched_spill_load_pct, .maxlen = sizeof(unsigned int), |