On Tuesday, May 29, 2012 4:08:23 pm Adrian Chadd wrote: > Hi Alexander and others, > > I've been tinkering with ath(4) IO scheduling and taskqueues. In order > to get proper "in order" TX IO occuring, I've placed ath_start() into > a taskqueue so now whenever ath_start() is called, it just schedules a > taskqueue entry to run. > > However, performance is worse. :-) > > Here's a schedgraph trace. > > http://people.freebsd.org/~adrian/ath/ktr.4-ath-iperf-using-taskqueue-for- tx.ktr.gz > > I've thrown this through schedgraph.py on stable/9 and I've found some > rather annoying behaviour. It seems that the ath0 taskqueue stays in > the "runq add" state for quite a long time (1.5ms and longer) because > something else is going on on CPU #0. > > I'm very confused about what's going on. I'd like a hand trying to > figure out why the schedgraph output is the way it is. > > Thanks!
As mentioned on IRC, you need to disable powerd and set machdep.idle=spin and get new traces. Right now your traces show multiple things executing on a single CPU. -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
