2013/4/15 Mats Liljegren <mats.liljeg...@enea.com>: > When I use lttng, I keep getting ticks. Without lttng, no ticks. It's the > same application I run, the same way. The only difference is whether lttng > logging has been started or not. > > The trace says "sched" as reason for not disabled ticks. Using "top" I can't > see any extra process/thread being created while my application runs, my > application gets 99-101% of the CPU. There are a couple of kworker threads > (3), a migration thread and a ksoftirq thread on the same CPU as my > application, though "top" gives no indication that they do any execution. > > Is this a known limitation of lttng, or is there something else going on > here?
I have no idea. But the "sched" reason means there is more than one task in the runqueue at some point. It can be a kthread indeed. Or a user task that gets migrated / woken up in the CPU. You'll need to check the sched:sched_switch tracepoint. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
