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* [patch] CFS scheduler, -v19
@ 2007-07-06 17:33 Ingo Molnar
  2007-07-08 17:46 ` Willy Tarreau
                   ` (3 more replies)
  0 siblings, 4 replies; 66+ messages in thread
From: Ingo Molnar @ 2007-07-06 17:33 UTC (permalink / raw)
  To: linux-kernel
  Cc: Linus Torvalds, Andrew Morton, Mike Galbraith, Arjan van de Ven,
	Thomas Gleixner, Dmitry Adamushko, Srivatsa Vaddagiri


i'm pleased to announce release -v19 of the CFS scheduler patchset.

The rolled-up CFS patch against today's -git kernel, v2.6.22-rc7, 
v2.6.22-rc6-mm1, v2.6.21.5 or v2.6.20.14 can be downloaded from the 
usual place:

    http://people.redhat.com/mingo/cfs-scheduler/
 
The biggest user-visible change in -v19 is reworked sleeper fairness: 
it's similar in behavior to -v18 but works more consistently across nice 
levels. Fork-happy workloads (like kernel builds) should behave better 
as well. There are also a handful of speedups: unsigned math, 32-bit 
speedups, O(1) task pickup, debloating and other micro-optimizations.

Changes since -v18:

 - merged the group-scheduling CFS-core changes from Srivatsa Vaddagiri. 
   This makes up for the bulk of the changes in -v19 but has no
   behavioral impact. The final group-fairness enabler patch is now a 
   small and lean add-on patch to CFS.

 - fix the bloat noticed by Andrew. On 32-bit it's now this:

      text    data     bss     dec     hex   filename
     24362    3905      24   28291    6e83   sched.o-rc7
     33015    2538      20   35573    8af5   sched.o-v18
     25805    2426      20   28251    6e5b   sched.o-v19

   so it's a net win compared to vanilla. On 64-bit it's even better:

      text    data     bss     dec     hex   filename
     35732   40314    2168   78214   13186   sched.o.x64-rc7
     41397   37642    2168   81207   13d37   sched.o.x64-v18
     36132   37410    2168   75710   127be   sched.o.x64-v19

   ( and there's also a +1.5K data win per CPU on x32, which is not
     shown here. [+3.0K data win per CPU on x64.] )

 - good number of core code updates, cleanups and streamlining.
   (Mike Galbraith, Srivatsa Vaddagiri, Dmitry Adamushko, me.)

 - use unsigned data types almost everywhere in CFS. This produces 
   faster and smaller code, and simplifies the logic.

 - turn as many 'u64' data types into 'unsigned long' as possible, to 
   reduce the 32-bit footprint and to reduce 64-bit arithmetics.

 - replaced the nr_running based 'sleep fairness' logic with a more 
   robust concept. The end-result is similar in behavior to v18, but 
   negative nice levels are handled much better in this scheme.

 - speedup: O(1) task pickup by Srivatsa Vaddagiri. [sleep/wakeup is
   O(log2(nr_running)).] This gives 5-10% better hackbench 100/500
   results on a 4-way box.

 - fix: set idle->sched_class back to &idle_sched_class in 
   migration_call(). (Dmitry Adamushko)

 - cleanup: use an enum for the sched_feature flags. (suggested by 
   Andrew Morton)

 - cleanup: turn the priority macros into inlines. (suggested by
   Andrew Morton)

 - (other cleanups suggested by Andrew Morton)

 - debug: split out the debugging data into CONFIG_SCHED_DEBUG.
 
As usual, any sort of feedback, bugreport, fix and suggestion is more 
than welcome!
 
	Ingo

^ permalink raw reply	[flat|nested] 66+ messages in thread
* Re: [patch] CFS scheduler, -v19
@ 2007-07-08 20:51 Al Boldi
  0 siblings, 0 replies; 66+ messages in thread
From: Al Boldi @ 2007-07-08 20:51 UTC (permalink / raw)
  To: linux-kernel

Ingo Molnar wrote:
> The biggest user-visible change in -v19 is reworked sleeper fairness:
> it's similar in behavior to -v18 but works more consistently across nice
> levels. Fork-happy workloads (like kernel builds) should behave better
> as well. There are also a handful of speedups: unsigned math, 32-bit
> speedups, O(1) task pickup, debloating and other micro-optimizations.

Thanks, these changes show an obvious improvement with heavy forklifters.  
But there is one strange artifact; fork response is not consistant over 
successive runs, i.e. sometimes it starves, sometimes it moves, and 
sometimes it flies.  It looks like it's dependent on some sched-stats to 
accumulate before it stablizes.

Also, fork/thread creation is one aspect of testing, but what about thread 
termination performance, which has to sync back to the creating thread?  How 
is that handled, and is there some code around that can test this?


Thanks!

--
Al


^ permalink raw reply	[flat|nested] 66+ messages in thread

end of thread, other threads:[~2007-10-17  0:02 UTC | newest]

Thread overview: 66+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-07-06 17:33 [patch] CFS scheduler, -v19 Ingo Molnar
2007-07-08 17:46 ` Willy Tarreau
2007-07-09 22:39   ` Ingo Molnar
2007-07-17 21:44     ` Willy Tarreau
2007-07-10  8:08 ` Mike Galbraith
2007-07-11 17:26   ` Bill Davidsen
2007-07-11 20:55     ` Ingo Molnar
2007-07-12 12:41       ` Bill Davidsen
2007-07-13 21:19       ` Bill Davidsen
2007-07-16 21:34         ` Chuck Ebbert
2007-07-16 21:55           ` Ingo Molnar
2007-07-17  4:22             ` Bill Davidsen
2007-07-17  5:01             ` Ian Kent
2007-07-17  7:45               ` Ingo Molnar
2007-07-17 11:17                 ` Ian Kent
2007-07-17 17:16                   ` Ingo Molnar
2007-07-18  1:24                     ` Bill Davidsen
2007-07-18  6:19                       ` Ian Kent
2007-07-17 16:30                 ` Chuck Ebbert
2007-07-17 21:16                 ` David Schwartz
2007-07-18  5:59                   ` Ian Kent
2007-07-18  7:54                     ` Ingo Molnar
2007-07-18 13:50                       ` Bill Davidsen
2007-07-18 17:23                       ` Linus Torvalds
2007-07-18 16:03                 ` Linus Torvalds
2007-07-18 17:31                   ` Ian Kent
2007-07-18 21:37                   ` Bill Davidsen
2007-07-19  8:53                     ` Ingo Molnar
2007-07-19 14:32                     ` Ingo Molnar
2007-07-19 17:06                       ` Bill Davidsen
2007-07-19 17:10                         ` Ingo Molnar
2007-07-19 17:17                         ` Ingo Molnar
2007-07-19 17:26                         ` Bill Davidsen
2007-07-19 17:42                           ` Ingo Molnar
2007-07-20  2:32                       ` Bill Davidsen
2007-07-19  8:16                   ` Ingo Molnar
2007-07-14 11:34 ` Markus
2007-07-14 15:11   ` Markus
2007-07-16  9:41     ` Ingo Molnar
2007-07-16 17:59       ` Markus
2007-07-17  7:37         ` Ingo Molnar
2007-07-17 13:06           ` Markus
2007-07-17 17:06             ` Ingo Molnar
2007-07-17 17:13               ` Ingo Molnar
2007-07-17 19:42               ` Markus
2007-07-17 20:09                 ` Ingo Molnar
2007-07-17 20:37                   ` Linus Torvalds
2007-07-17 20:43                     ` Ingo Molnar
2007-07-17 22:03                       ` Markus
2007-07-20 22:26                       ` Markus
2007-07-22 11:59                         ` konqueror suddenly vanishing, "konqueror: Fatal IO error: client killed" Ingo Molnar
2007-07-22 14:26                           ` Markus
2007-08-09 17:34                       ` [patch] CFS scheduler, -v19 Markus
2007-08-10  7:46                         ` Ingo Molnar
2007-08-14 17:15                           ` Markus
2007-10-17  0:02                       ` Markus
2007-07-14 17:19 ` Ed Tomlinson
2007-07-15  5:25   ` Mike Galbraith
2007-07-15 12:53     ` Markus
2007-07-15 19:46       ` Mike Galbraith
2007-07-15 21:11         ` Markus
2007-07-16  6:42           ` Mike Galbraith
2007-07-16  8:00     ` Ingo Molnar
2007-07-16  9:17   ` Ingo Molnar
2007-07-16 11:10     ` Ed Tomlinson
  -- strict thread matches above, loose matches on Subject: below --
2007-07-08 20:51 Al Boldi

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