Re: tasklets vs. workqueues

[Martin Diehl]

On Wed, 25 Feb 2004, George Anzinger wrote:

> >>Being in process context, you can also change the priority and schedule policy 
> >>as needed to fit your application, while you are rather stuck with tasklets in 
> >>this regard.
> > 
> > 
> > How would one do that correctly? Something like
> 
> Depends on where you want to be when you do it.  From user land you would do 
> exactly what the attached program does.  In SMP you would, likely, want to do 
> all the tasks in the work queue (one per cpu).

Ok, thanks - primary concern was kernelthread anyway. Sorry if I wasn't 
clear enough.

>  From the kernel, again calling setscheduler() is the way to go.  I am not sure 
> what is in the community tree just now, but if I recall properly, the scheduler 
> itself does this so, one should be able to copy that code.
> 
> Ah, yes, there it is in  migration_thread().  It calls setscheduler().

Basically yes. Except that setscheduler is static in kernel/sched.c so one 
has to use sys_sched_setscheduler (and add some EXPORT_SYMBOL for it). And 
of course it needs the set_fs(KERNEL_DS) magic.

Thanks, I was hoping I've missed some simple "official" entry point there 
to create a SCHED_FIFO kernel thread from a module.

Martin

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