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Subject[tg_shares_up rewrite v4 00/11] reduce overhead for tg->shares distribution
This is v4 of the tg_shares_up re-write previously posted at:
http://lkml.org/lkml/2010/10/16/17

Corrected versus the previous version is the quilt patch-strip level.

The key idea behind this patchset is an idea of Peter Zijlstra'a to compute
global loads as a function of local averages, avoiding the cpu-cpu interactions
which previously plagued tg_shares_up.

Beyond bug fixes not much material has changed since v1 as results seem
favourable/stable.

Changes:
v4
all patches
- fix "-p0" stripping

v3 (http://lkml.org/lkml/2010/11/11/526)
sched-rework-tg_shares_up.patch
- remove lint: {max,min}_sched_shares_ratelimit from sysctl.c

sched-tg-ondemand.patch
- (bug fix) fix synchronization on leaf_cfs_rq_list removal during task_group reclaim.
- fix !CONFIG_FAIR_GROUP_SCHED build
- fix comment on what task_group_lock protects

sched-tg-global_update_load.patch
- add missing arguments to update_cfs_load() in !CONFIG_FAIR_GROUP_SCHED case

v2 (http://lkml.org/lkml/2010/11/10/618)
sched-rework-tg_shares_up.patch
- (bug fix) use owning tg->shares value in effective_load
- remove redundant cfs_rq_of() in {enqueue,dequeue}_entity

sched-tg-add-shares_window_sysctl.patch
- update comment on sysctl interpretation

sched-tg-fix-update_cfs_load.patch
- update comment to reflect periods instead of foldings (more intuitive)

Some motivation again:
24 thread Intel box, 150 active cgroups, multiple threads/group, system load at ~90% (sample size=10s):
tip:
2.64% [k] tg_shares_up <!>
0.15% [k] __set_se_shares

patched:
0.02% [k] update_cfs_load
0.01% [k] update_cpu_load
0.00% [k] update_cfs_shares

Fairness coverage for the above at: http://rs5.risingnet.net/~pjt/patches/shares_data_v1.txt

Thanks,

- Paul



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