On 2/3/2014 4:54 AM, Morten Rasmussen wrote:
I'm therefore not convinced that idle state index is the right thing to give the scheduler. Using a cost metric would be better in my opinion.
I totally agree with this, and we may need two separate cost metrics 1) A latency driven one 2) A performance impact on first one is pretty much the exit latency related time, sort of a "expected time to first instruction" (currently menuidle has the 99.999% worst case number, which is not useful for this, but is a first approximation). This is obviously the dominating number for expected-short running tasks second on is more of a "is there any cache/TLB left or is it flushed" kind of metric. It's more tricky to compute, since what is the cost of an empty cache (or even a cache migration) after all.... .... but I suspect it's in part what the scheduler will care about more for expected-long running tasks. -- 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/
