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From: Mike Galbraith <efault@gmx.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Brian Rogers <brian@xyzw.org>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [BUG] How to get real-time priority using idle priority
Date: Wed, 14 Jan 2009 07:02:45 +0100	[thread overview]
Message-ID: <1231912965.956.11.camel@marge.simson.net> (raw)
In-Reply-To: <20090114053106.GA10410@elte.hu>

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




  reply	other threads:[~2009-01-14  6:03 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-11 10:58 [BUG] How to get real-time priority using idle priority Brian Rogers
2009-01-12  5:09 ` Mike Galbraith
2009-01-12 13:03   ` Mike Galbraith
2009-01-12 13:14     ` Ingo Molnar
2009-01-12 15:23       ` Mike Galbraith
2009-01-12 15:24         ` Ingo Molnar
2009-01-13  1:05       ` Brian Rogers
2009-01-13  2:58         ` Mike Galbraith
2009-01-14  5:13           ` Mike Galbraith
2009-01-14  5:31             ` Ingo Molnar
2009-01-14  6:02               ` Mike Galbraith [this message]
2009-01-14  7:35                 ` Ingo Molnar
2009-01-15  9:28         ` Mike Galbraith
2009-01-15 10:14           ` Peter Zijlstra
2009-01-15 10:30             ` Mike Galbraith
2009-01-15 11:37               ` Mike Galbraith
2009-01-15 11:41                 ` Peter Zijlstra
2009-01-15 12:54                   ` Ingo Molnar
2009-01-15 13:05                     ` Peter Zijlstra
2009-01-15 13:15                       ` Ingo Molnar
2009-01-15 13:16                     ` Peter Zijlstra
2009-01-15 12:07           ` Brian Rogers
2009-01-12 20:46     ` [patch take 2] " Mike Galbraith
2009-01-12 20:50       ` Mike Galbraith

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