On Fri, 2012-08-17 at 00:02 +1000, Michael Ellerman wrote: > You do want to guarantee that the task will always be subject to the > breakpoint, even if it moves cpus. So is there any way to guarantee that > other than reserving a breakpoint slot on every cpu ahead of time?
That's not how regular perf works.. regular perf can overload hw resources at will and stuff is strictly per-cpu. So the regular perf record has perf_event_attr::inherit enabled by default, this will result in it creating a per-task-per-cpu event for each cpu and this will succeed because there's no strict reservation to avoid/detect starvation against perf_event_attr::pinned events. For regular (!pinned) events, we'll RR the created events on the available hardware resources. HWBP does things completely different and reserves a slot over all CPUs for everything, thus stuff completely falls apart. -- 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/
