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Re: [PATCH 1/2] sched: fix RT task-wakeup logic

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From: Dmitry Adamushko
Subject: Re: [PATCH 1/2] sched: fix RT task-wakeup logic
Date: Wednesday, April 23, 2008 - 7:29 am

2008/4/23 Gregory Haskins <ghaskins@novell.com>:

Acked-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>


I have to look at the second patch more thoroughly... but I guess,
we'd be better off opting for something more simple/less complex (it
looks a bit heavy at the first glance).

This patch already fixes an 'obvious' problem in task_wake_up_rt() and
narrows down the scope of the original problem.

For the original scenario (as well as for its variants with SCHED_FIFO
and != priorities) push_rt_tasks() is 'delayed' untill a reschedule
(which is already pending and should take place shortly... provided
'bounded/short' latencies :-)

For T0,T1 having equal prios + SCHED_RR, T1 (which can't be migrated
due to its affinity) will wait till T0's timeslice expires
and for SCHED_FIFO -- till T0 releases a CPU.

The 'optimal' way would be moving T0 immediatelly off this cpu.


-- 
Best regards,
Dmitry Adamushko
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Messages in current thread:
[PATCH 0/2] sched: refreshes, Gregory Haskins, (Mon Apr 21, 11:10 am)
[PATCH 1/2] sched: push rt tasks only if newly activated t ..., Gregory Haskins, (Mon Apr 21, 11:10 am)
[PATCH 2/2] sched: Use a 2-d bitmap for searching lowest-p ..., Gregory Haskins, (Mon Apr 21, 11:10 am)
Re: [PATCH 0/2] sched: refreshes, Ingo Molnar, (Mon Apr 21, 12:33 pm)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Dmitry Adamushko, (Tue Apr 22, 8:30 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Steven Rostedt, (Tue Apr 22, 8:51 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Gregory Haskins, (Tue Apr 22, 9:38 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Dmitry Adamushko, (Wed Apr 23, 1:05 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Dmitry Adamushko, (Wed Apr 23, 2:53 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Gregory Haskins, (Wed Apr 23, 3:03 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Dmitry Adamushko, (Wed Apr 23, 3:23 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Gregory Haskins, (Wed Apr 23, 3:54 am)
[RFC PATCH 0/2] sched fixes for suboptimal balancing, Gregory Haskins, (Wed Apr 23, 4:13 am)
[PATCH 1/2] sched: fix RT task-wakeup logic, Gregory Haskins, (Wed Apr 23, 4:13 am)
[PATCH 2/2] sched: prioritize non-migratable tasks over mi ..., Gregory Haskins, (Wed Apr 23, 4:13 am)
Re: [PATCH 1/2] sched: push rt tasks only if newly activat ..., Dmitry Adamushko, (Wed Apr 23, 4:20 am)
Re: [PATCH 1/2] sched: fix RT task-wakeup logic, Steven Rostedt, (Wed Apr 23, 5:54 am)
Re: [PATCH 2/2] sched: prioritize non-migratable tasks ove ..., Steven Rostedt, (Wed Apr 23, 5:58 am)
Re: [PATCH 2/2] sched: prioritize non-migratable tasks ove ..., Gregory Haskins, (Wed Apr 23, 6:11 am)
Re: [PATCH 1/2] sched: fix RT task-wakeup logic, Dmitry Adamushko, (Wed Apr 23, 7:29 am)
Re: [PATCH 1/2] sched: fix RT task-wakeup logic, Gregory Haskins, (Thu Apr 24, 4:56 am)
[(RESEND) PATCH] sched: fix RT task-wakeup logic, Gregory Haskins, (Mon Apr 28, 9:30 am)
Re: [RFC PATCH 0/2] sched fixes for suboptimal balancing, Ingo Molnar, (Mon Apr 28, 11:55 am)
Re: [(RESEND) PATCH] sched: fix RT task-wakeup logic, Ingo Molnar, (Tue Apr 29, 7:35 am)