Messages in this thread | | | Date | Fri, 21 Dec 2001 09:33:21 -0800 | From | Mike Kravetz <> | Subject | Re: [RFC] Scheduler issue 1, RT tasks ... |
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On Fri, Dec 21, 2001 at 09:19:04AM -0800, Davide Libenzi wrote: > On Fri, 21 Dec 2001, Mike Kravetz wrote: > > > Some time back, I asked if anyone had any RT benchmarks and got > > little response. Performance (latency) degradation for RT tasks > > while implementing new schedulers was my concern. Does anyone > > have ideas about how we should measure/benchmark this? My > > 'solution' at the time was to take a scheduler heavy benchmark > > like reflex, and simply make all the tasks RT. This wasn't very > > 'real world', but at least it did allow me to compare scheduler > > overhead in the RT paths of various scheduler implementations. > > Mike, a better real world test would be to have a variable system runqueue > load with the wakeup of an rt task and measuring the latency of the rt > task under various loads. > This can be easily implemented with cpuhog ( that load the runqueue ) plus > the LatSched ( scheduler latency sampler ) that will measure the exact > latency in CPU cycles.
Right! Any ideas on variable system runqueue load? Should those other tasks be RT or OTHER? a mix? I would suspect that we would want multiple RT tasks on the runqueue or at least in the system (otherwise why worry about global semantics?).
However, I would feel better about this if someone had a real world load involving RT tasks on a SMP system. At least then we could try to simulate a load someone cares about.
-- Mike - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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