* Ting Yang <[EMAIL PROTECTED]> wrote: > then how much time is needed for "curr" to build a 2 * 32 difference > on fair_key, with every 1 ms it updates fair_key by 1/32 ? 2 * 32 * > 32 !
yes - but the "*32" impacts the rescheduling granularity, the "/32" impacts the speed of how the key moves. So the total execution speed of the nice -10 task is still "*32" of a nice 0 task - it's just that not only it gets 32 times more CPU time, it also gets it at 32 times larger chunks at once. But the rescheduling granularity does _not_ impact the CPU share the task gets, so there's no quadratic effect. but this is really simple to test: boot up CFS, start two infinite loops, one at nice 0 and one at nice +10 and look at it via "top" and type 's 60' in top to get a really long update interval for precise results. You wont see quadratically less CPU time used up by the nice +10 task, you'll see it getting the intended 1/32 share of CPU time. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/