Re: [BUG] How to get real-time priority using idle priority

[Mike Galbraith]

On Wed, 2009-01-14 at 06:31 +0100, Ingo Molnar wrote:
> What about increasing the weight of SCHED_IDLE tasks from 1 to 2 or 3? 
> That still makes them mega-nice (which is more than enough), but should 
> make the math a lot less borderline.

The weight is currently 2, inv_weight is 1 << 31, which is correct.

I implemented the advance min_vruntime at nice 0 thing, and that seems
to work fine.  SCHED_IDLE tasks slam right as they execute, but check
out how _far_ right they slam.  This was with the build pinned to cpu 3,
so no migration issues.  I'll try weight of 3.

cfs_rq[3]:
  .exec_clock                    : 0.000000
  .MIN_vruntime                  : 281842722.745713
  .min_vruntime                  : 370490.315434
  .max_vruntime                  : 281843966.887081
  .spread                        : 1244.141368
  .spread0                       : 85467.080507
  .nr_running                    : 6
  .load                          : 12
  .nr_spread_over                : 0

rt_rq[3]:
  .rt_nr_running                 : 0
  .rt_throttled                  : 0
  .rt_time                       : 0.000000
  .rt_runtime                    : 950.000000

runnable tasks:
            task   PID         tree-key  switches  prio     exec-runtime         sum-exec        sum-sleep
----------------------------------------------------------------------------------------------------------
            make 29977 281843914.902150       171   120               0               0               0.000000               0.000000               0.000000
            make 30530 281842722.745713         6   120               0               0               0.000000               0.000000               0.000000
             gcc 30584 281843921.282161         1   120               0               0               0.000000               0.000000               0.000000
              sh 30590 281843966.887081         2   120               0               0               0.000000               0.000000               0.000000
             gcc 30591 281843882.274316         1   120               0               0               0.000000               0.000000               0.000000
R            cc1 30592    372734.946902         5   120               0               0               0.000000               0.000000               0.000000



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/