> The cache misses dropped by ~23% and migrations dropped by ~28%. I > really believe that the idle_balance() hurts performance, and not just > for something like hackbench, but the aggressive nature for migration > that idle_balance() causes takes a large hit on a process' cache. > > Think about it some more, just because we go idle isn't enough reason to > pull a runable task over. CPUs go idle all the time, and tasks are woken > up all the time. There's no reason that we can't just wait for the sched > tick to decide its time to do a bit of balancing. Sure, it would be nice > if the idle CPU did the work. But I think that frame of mind was an > incorrect notion from back in the early 2000s and does not apply to > today's hardware, or perhaps it doesn't apply to the (relatively) new > CFS scheduler. If you want aggressive scheduling, make the task rt, and > it will do aggressive scheduling. >
How is it that the normal tick based load balancing gets it correctly while the idle_balance gets is wrong? Can it because of the different cpu_idle_type? -- Thanks and Regards Srikar Dronamraju -- 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/
