On Friday, February 17, 2017 08:48:57 PM Andriy Gapon wrote: > > First, an example, three consecutive entries for the same thread (from top to > bottom): > KTRGRAPH group:"thread", id:"zio_write_intr_3 tid 100260", state:"sleep", > attributes: prio:84, wmesg:"-", lockname:"(null)" > KTRGRAPH group:"thread", id:"zio_write_intr_3 tid 100260", state:"spinning", > attributes: lockname:"sched lock 1" > KTRGRAPH group:"thread", id:"zio_write_intr_3 tid 100260", state:"running", > attributes: none > > Any automatic analysis tool including schedgraph.py will assume that the > thread > ends up in the running state. In reality, of course, the thread is in the > sleeping state. > The confusing trace is a result of logging the thread's intention to switch > out > in mi_switch() before calling sched_switch(). In ULE's sched_switch() we > acquire the "TDQ_LOCK" which could be contested. In that case the thread > spins > waiting for the lock to be released. This is reported as "spinning" and then > "running" states. > > I would like to fix that, but not sure how to do that best. > One idea is to move the mi_switch() trace closer to the cpu_switch() call > similarly to DTrace sched:cpu-off and sched:cpu-on probes.
I think this is the right fix. -- John Baldwin _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"