I think there are dual efforts in progress here. For ODP purposes, the 'full RT' kernel probably should not be required even if/when we get NO_HZ_FULL/cpu isolation working there. However for those users who want to work within the kernel stacks rather than from isolated cores, full RT control of scheduling latencies may be a requirement. So we will have efforts to optimize latencies on the RT kernel as well as providing support for operation on isolated cores with minimal interference from the kernel... RT or otherwise. As per interrupt latency, that is mostly a function of the drivers selected in a given install since the generic parts of the kernel already have interrupts disabled for the briefest times possible... and interrupt contexts operate independently of the scheduler itself. Where 'threaded ISRs' are configured, interrupts not explicitly prevented from being threaded will of course have most of their operation shifted into schedulable contexts - but in cases where that induces unacceptable latencies specific interrupts may be forced to remain unthreaded to minimize any contention for CPU time. On Mon, Mar 10, 2014 at 6:37 PM, Ola Liljedahl