On Monday 12 March 2007 05:11, Al Boldi wrote: > Al Boldi wrote: > > BTW, another way to show these hickups would be through some kind of a > > cpu/proc timing-tracer. Do we have something like that? > > Here is something like a tracer. > > Original idea by Chris Friesen, thanks, from this post: > http://marc.theaimsgroup.com/?l=linux-kernel&m=117331003029329&w=4 > > Try attached chew.c like this: > Boot into /bin/sh. > Run chew in one console. > Run nice chew in another console. > Watch timings. > > Console 1: ./chew
> Console 2: nice -10 ./chew > pid 669, prio 10, out for 5 ms > pid 669, prio 10, out for 65 ms One full expiration > pid 669, prio 10, out for 6 ms > pid 669, prio 10, out for 65 ms again > Console 2: nice -15 ./chew > pid 673, prio 15, out for 6 ms > pid 673, prio 15, out for 95 ms again and so on.. > OTOH, mainline is completely smooth, albeit huge drop-outs. Heh. That's not much good either is it. > Thanks! 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. -- -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/
