Commit graph

10 commits

Author SHA1 Message Date
Ingo Molnar
f681bbd656 sched: turn off WAKEUP_OVERLAP
WAKEUP_OVERLAP is not a winner on a 16way box, running psql+sysbench:

       .27-rc7-NO_WAKEUP_OVERLAP  .27-rc7-WAKEUP_OVERLAP
-------------------------------------------------
    1:             694              811    +14.39%
    2:            1454             1427    -1.86%
    4:            3017             3070    +1.70%
    8:            5694             5808    +1.96%
   16:           10592            10612    +0.19%
   32:            9693             9647    -0.48%
   64:            8507             8262    -2.97%
  128:            8402             7087    -18.55%
  256:            8419             5124    -64.30%
  512:            7990             3671    -117.62%
-------------------------------------------------
  SUM:           64466            55524    -16.11%

... so turn it off by default.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-22 16:29:00 +02:00
Peter Zijlstra
15afe09bf4 sched: wakeup preempt when small overlap
Lin Ming reported a 10% OLTP regression against 2.6.27-rc4.

The difference seems to come from different preemption agressiveness,
which affects the cache footprint of the workload and its effective
cache trashing.

Aggresively preempt a task if its avg overlap is very small, this should
avoid the task going to sleep and find it still running when we schedule
back to it - saving a wakeup.

Reported-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-22 16:28:32 +02:00
Peter Zijlstra
efc2dead2c sched: enable LB_BIAS by default
Yanmin reported a significant regression on his 16-core machine due to:

  commit 93b75217df
  Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
  Date:   Fri Jun 27 13:41:33 2008 +0200

Flip back to the old behaviour.

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 08:18:02 +02:00
Peter Zijlstra
f5bfb7d9ff sched: bias effective_load() error towards failing wake_affine().
Measurement shows that the difference between cgroup:/ and cgroup:/foo
wake_affine() results is that the latter succeeds significantly more.

Therefore bias the calculations towards failing the test.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-27 14:31:47 +02:00
Peter Zijlstra
2398f2c6d3 sched: update shares on wakeup
We found that the affine wakeup code needs rather accurate load figures
to be effective. The trouble is that updating the load figures is fairly
expensive with group scheduling. Therefore ratelimit the updating.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-27 14:31:45 +02:00
Peter Zijlstra
93b75217df sched: disable source/target_load bias
The bias given by source/target_load functions can be very large, disable
it by default to get faster convergence.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-27 14:31:44 +02:00
Peter Zijlstra
c9c294a630 sched: fix calc_delta_asym()
calc_delta_asym() is supposed to do the same as calc_delta_fair() except
linearly shrink the result for negative nice processes - this causes them
to have a smaller preemption threshold so that they are more easily preempted.

The problem is that for task groups se->load.weight is the per cpu share of
the actual task group weight; take that into account.

Also provide a debug switch to disable the asymmetry (which I still don't
like - but it does greatly benefit some workloads)

This would explain the interactivity issues reported against group scheduling.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-27 14:31:28 +02:00
Peter Zijlstra
a7be37ac8e sched: revert the revert of: weight calculations
Try again..

initial commit: 8f1bc385cf
revert: f9305d4a09

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-27 14:31:27 +02:00
Mike Galbraith
6492c7f83e sched: trivial sched_features cleanup
Remove unused debug/tuning features.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-10 12:38:17 +02:00
Peter Zijlstra
f00b45c145 sched: /debug/sched_features
provide a text based interface to the scheduler features; this saves the
'user' from setting bits using decimal arithmetic.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-19 19:45:00 +02:00