2013/3/25 Christoph Lameter <c...@linux.com>: > On Fri, 22 Mar 2013, Paul E. McKenney wrote: > >> On Fri, Mar 22, 2013 at 02:38:58PM +0000, Christoph Lameter wrote: >> > On Thu, 21 Mar 2013, Paul E. McKenney wrote: >> > >> > > So, how long of busy periods are you contemplating for your SCHED_FIFO >> > > threads? Is it possible to tune/adjust the offending per-CPU ktheads >> > > to wake up less frequently than that time? >> > >> > Test programs right now run 10 seconds. 30 seconds would definitely be >> > enough for the worst case. >> >> OK, that might be doable for some workloads. What happens when you >> try tuning the 2-second wakeup interval to (say) 45 seconds? > > The vm kernel threads do no useful work if no system calls are being done. > If there is no kernel action then they can be deferred indefinitely. >
We can certainly add some user deferrable timer_list. But that's going to be for extreme usecases (those who require pure isolation) because we'll need to settle that with a timer reprogramming into user/kernel boundaries. That won't be free. -- 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/
