On Wed, May 15, 2013 at 11:06:53AM -0400, Don Zickus wrote: > Coming into the middle of the thread is always hard, but why/how does perf > disable nohz_full? I didn't think the hardware events of perf would cause > problems as they are no different than an irq. Curious.
Yah, right :-) So I think what happens is that when we enter kernel space for whatever reason (say NMIs for a watchdog), we kill the magic NO_HZ state that allows a single task that's stuck in userspace to effectively have the tick disabled. But yeah, the initial patch was a tad light on detail, so I'll have to let Steve and Frederic expand / correct. -- 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/
