On Monday 12 March 2007 15:42, Al Boldi wrote: > Con Kolivas wrote: > > On Monday 12 March 2007 08:52, Con Kolivas wrote: > > > And thank you! I think I know what's going on now. I think each > > > rotation is followed by another rotation before the higher priority > > > task is getting a look in in schedule() to even get quota and add it to > > > the runqueue quota. I'll try a simple change to see if that helps. > > > Patch coming up shortly. > > > > Can you try the following patch and see if it helps. There's also one > > minor preemption logic fix in there that I'm planning on including. > > Thanks! > > Applied on top of v0.28 mainline, and there is no difference. > > What's it look like on your machine?
The higher priority one always get 6-7ms whereas the lower priority one runs 6-7ms and then one larger perfectly bound expiration amount. Basically exactly as I'd expect. The higher priority task gets precisely RR_INTERVAL maximum latency whereas the lower priority task gets RR_INTERVAL min and full expiration (according to the virtual deadline) as a maximum. That's exactly how I intend it to work. Yes I realise that the max latency ends up being longer intermittently on the niced task but that's -in my opinion- perfectly fine as a compromise to ensure the nice 0 one always gets low latency. Eg: nice 0 vs nice 10 nice 0: pid 6288, prio 0, out for 7 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms pid 6288, prio 0, out for 6 ms nice 10: pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 66 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms pid 6290, prio 10, out for 6 ms exactly as I'd expect. If you want fixed latencies _of niced tasks_ in the presence of less niced tasks you will not get them with this scheduler. What you will get, though, is a perfectly bound relationship knowing exactly what the maximum latency will ever be. Thanks for the test case. It's interesting and nice that it confirms this scheduler works as I expect it to. -- -ck - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
