Date: Wed, 18 Jun 2003 15:34:02 -0400
From: Joe Korty <joe.korty@ccur.com>
To: george anzinger <george@mvista.com>
Cc: lkml <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: O(1) scheduler seems to lock up on sched_FIFO and sched_RR tasks
Message-ID: <20030618193053.GA15576@tsunami.ccur.com>
Reply-To: joe.korty@ccur.com
References: <3EF0979C.8060603@mvista.com>
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On Wed, Jun 18, 2003 at 09:47:24AM -0700, george anzinger wrote:
> It seems that once a SCHED_FIFO or SCHED_RR tasks gets control it does 
> not yield to other tasks of higher priority.
> 
> Attached is a test program (busyloop) that just loops doing 
> gettimeofday() for the requested time and a little utility (rt) to run 
> programs at real time priorities.
> 
> Here is an annoted example of the problem:
> 
> First, become root then:
> > rt 90 bash        <-- run bash at priority 90 SCHED_RR
> > rt -f 30 busyloop 10 &  <-- busyloop 10 at priority 30 SCHED_FIFO
> 
> At this point the bash at priority 90 should be available, but is not. 
>  When the 10 second busyloop completes, bash returns.


Hi George,
 When I boost the priority of each of the per-cpu 'events/%d' daemon to
96, the problem goes away.

Joe
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