>this is the second release of the CFS (Completely Fair Scheduler)
>patchset, against v2.6.21-rc7:
>
>
http://redhat.com/~mingo/cfs-scheduler/sched-cfs-v2.patch
>
>i'd like to thank everyone for the tremendous amount of feedback and
>testing the v1 patch got - i could hardly keep up with just reading the
>mails! Some of the stuff people addressed i couldnt implement yet, i
>mostly concentrated on bugs, regressions and debuggability.
>
>there's a fair amount of churn:
>
> 15 files changed, 456 insertions(+), 241 deletions(-)
>
>But it's an encouraging sign that there was no crash bug found in v1,
>all the bugs were related to scheduling-behavior details. The code was
>tested on 3 architectures so far: i686, x86_64 and ia64. Most of the
>code size increase in -v2 is due to debugging helpers, they'll be
>removed later. (The new /proc/sched_debug file can be used to see the
>fine details of CFS scheduling.)
>
>Changes since -v1:
>
> - make nice levels less starvable. (reported by Willy Tarreau)
>
> - fixed child-runs first. A /proc/sys/kernel/sched_child_runs_first
> flag can be used to turn it on/off. (This might fix the Kaffeine bug
> reported by S.Çağlar Onur <)
>
> - changed SCHED_FAIR back to SCHED_NORMAL (suggested by Con Kolivas)
>
> - UP build fix. (reported by Gabriel C)
>
> - timer tick micro-optimization (Dmitry Adamushko)
>
> - preemption fix: sched_class->check_preempt_curr method to decide
> whether to preempt after a wakeup (or at a timer tick). (Found via a
> fairness-test-utility written for CFS by Mike Galbraith)
>
> - start forked children with neutral statistics instead of trying to
> inherit them from the parent: Willy Tarreau reported that this
> results in better behavior on extreme workloads, and it also
> simplifies the code quite nicely. Removed sched_exit() and the
> ->task_exit() methods.
>
> - make nice levels independent of the sched_granularity value
>
> - new /proc/sched_debug file listing runqueue details and the rbtree
>
> - new SCH-* fields in /proc/<NR>/status to see scheduling details
>
> - new cpu-hog feature (off by default) and sysctl tunable to set it:
> /proc/sys/kernel/sched_max_hog_history_ns tunable defaults to
> 0 (off). Positive values are meant the maximum 'memory' that the
> scheduler has of CPU hogs.
>
> - various code cleanups
>
> - added more statistics temporarily: sum_exec_runtime,
> sum_wait_runtime.
>
> - added -CFS-v2 to EXTRAVERSION
>
>as usual, any sort of feedback, bugreports, fixes and suggestions are
>more than welcome,
>
> Ingo
