OpenCloudOS-Kernel/kernel/sched
Paul Turner 9ee474f556 sched: Maintain the load contribution of blocked entities
We are currently maintaining:

  runnable_load(cfs_rq) = \Sum task_load(t)

For all running children t of cfs_rq.  While this can be naturally updated for
tasks in a runnable state (as they are scheduled); this does not account for
the load contributed by blocked task entities.

This can be solved by introducing a separate accounting for blocked load:

  blocked_load(cfs_rq) = \Sum runnable(b) * weight(b)

Obviously we do not want to iterate over all blocked entities to account for
their decay, we instead observe that:

  runnable_load(t) = \Sum p_i*y^i

and that to account for an additional idle period we only need to compute:

  y*runnable_load(t).

This means that we can compute all blocked entities at once by evaluating:

  blocked_load(cfs_rq)` = y * blocked_load(cfs_rq)

Finally we maintain a decay counter so that when a sleeping entity re-awakens
we can determine how much of its load should be removed from the blocked sum.

Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.585389902@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-24 10:27:22 +02:00
..
Makefile sched: Move cputime code to its own file 2012-08-20 13:05:17 +02:00
auto_group.c sched: Clean up parameter passing of proc_sched_autogroup_set_nice() 2012-03-02 12:23:49 +01:00
auto_group.h
clock.c
core.c sched: Maintain the load contribution of blocked entities 2012-10-24 10:27:22 +02:00
cpupri.c sched: Fix minor code style issues 2012-07-26 11:47:00 +02:00
cpupri.h
cputime.c vtime: Consolidate system/idle context detection 2012-09-25 15:42:37 +02:00
debug.c sched: Maintain the load contribution of blocked entities 2012-10-24 10:27:22 +02:00
fair.c sched: Maintain the load contribution of blocked entities 2012-10-24 10:27:22 +02:00
features.h sched: cpu_power: enable ARCH_POWER 2012-09-13 16:52:06 +02:00
idle_task.c sched/nohz: Rewrite and fix load-avg computation -- again 2012-07-05 20:58:13 +02:00
rt.c sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW 2012-09-13 16:52:04 +02:00
sched.h sched: Maintain the load contribution of blocked entities 2012-10-24 10:27:22 +02:00
stats.c sched: Remove sched_switch 2012-01-27 13:28:53 +01:00
stats.h
stop_task.c sched: Fix migration thread runtime bogosity 2012-08-13 18:41:55 +02:00