On Tue, Jun 06, 2006 at 08:51:13PM +0200, Lars Luthman wrote: > On Tue, 2006-06-06 at 14:31 -0400, Joshua Boyd wrote: > > On Tue, Jun 06, 2006 at 01:39:31PM -0400, Lee Revell wrote: > > > On Tue, 2006-06-06 at 11:10 -0400, Joshua Boyd wrote: > > > > I have CONFIG_PREEMPT and CONFIG_PREEMPT_BKL on. My application runs > > > > with SCHED_FIFO and has an elevated priority, but not realtime > > > > priority. When I tried setting it to realtime priority it grinds the > > > > networking, control panel, and VGA display applications to a halt. > > > > > > Uhhh, SCHED_FIFO and "realtime priority" are the same thing. > > > > > > Can you be more specific? > > > > setpriority(PRIO_PROCESS, 0, -20); > > > > I was under the impression that that set priority to a "realtime" > > priority, although rereading the man page I don't see any specific > > correlation listed between -20 and realtime. > > > > I also do: sched_setscheduler(0, SCHED_FIFO, &sp); > > > > When I do the setpriority to -20, basically everything other than the > > main application grinds to a halt. If I use -10 instead, other programs > > work fine, but networking is then allowed to interfere with the main > > program. > > Just checking - is the SCHED_FIFO thread ever yielding the CPU? Or is it > just running a loop without ever sleeping or waiting for some lock? Every thread in the process (since as I understand it, every thread in the process is being set to sched_fifo) blocks on something. The video thread blocks on the video card, the audio thread on the audio card, and most other threads block on pthread_cond_waits (one house keeping thread blocks on sleeps).
