Re: O(1) scheduler seems to lock up on sched_FIFO and sched_RR ta sks

'joe.korty@ccur.com'
2003-06-19T04:21:39Z

On Wed, Jun 18, 2003 at 06:44:42PM -0700, Perez-Gonzalez, Inaky wrote:
>
> Now that we are at that, it might be wise to add a higher-than-anything
> priority that the kernel code can use (what would be 100 for user space,
> but off-limits), so even FIFO 99 code in user space cannot block out
> the migration thread, keventd and friends.

I would prefer users have the ability to put one or two truly critical RT
tasks above keventd & family. Such tasks would have to follow certain rules
.. run & sleep quick .. limited or no device IO .. most communication to
other tasks through shared memory .. possibly others.

There are those willing to follow whatever rules necessary & split up their
application into tasks any which way in order to get high responsiveness to a
critical but small part of their application. If you follow the rules, you
should be allowed to put a carefully crafted task above the system daemons
(with the possible exception of the migration daemon).

Joe