linux/include
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
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-10-08 07:14:06 +09:00
asm-generic UAPI: Remove empty non-UAPI Kbuild files 2012-10-17 12:31:15 +01:00
clocksource
crypto Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux 2012-10-14 13:39:34 -07:00
drm UAPI: Remove empty non-UAPI Kbuild files 2012-10-17 12:31:15 +01:00
keys KEYS: Asymmetric key pluggable data parsers 2012-10-08 13:50:13 +10:30
linux sched: Maintain the load contribution of blocked entities 2012-10-24 10:27:22 +02:00
math-emu
media Merge branch 'exynos-drm-next' of git://git.infradead.org/users/kmpark/linux-samsung into drm-next 2012-10-07 21:06:33 +10:00
memory
misc
net ipv4: Add FLOWI_FLAG_KNOWN_NH 2012-10-08 17:42:36 -04:00
pcmcia
ras
rdma infiniband: pass rdma_cm module to netlink_dump_start 2012-10-07 00:30:56 -04:00
rxrpc
scsi SCSI misc on 20121012 2012-10-13 10:57:01 +09:00
sound Sound updates for 3.7-rc1 2012-10-09 07:07:14 +09:00
target target: Add target_submit_cmd_map_sgls for SGL fabric memory passthrough 2012-10-02 14:16:08 -07:00
trace Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2012-10-10 10:49:20 +09:00
uapi TTY fixes for 3.7-rc2 2012-10-19 11:28:59 -07:00
video fbdev updates for 3.7 2012-10-12 10:21:02 +09:00
xen Bug-fixes: 2012-10-24 05:17:27 +03:00
Kbuild UAPI: Remove empty non-UAPI Kbuild files 2012-10-17 12:31:15 +01:00