* David Miller <davem@xxxxxxxxxxxxx> wrote: > From: Ingo Molnar <mingo@xxxxxxx> > Date: Fri, 5 Dec 2008 09:42:33 +0100 > > > Please let me repeat: it's a _fundamental_ thesis of performance > > instrumentation to not disturb the monitored context. Your insistence > > on _stopping_ the monitored task breaks that fundamental axiom! > > This is only a problem if you make your measurement quantums too small. But if you make the measurement long enough - say we make it 100,000 usecs, then 0.2 usecs of delay between two read()s is insignificant statistically, right? It's a 1:500,000 ratio. Scheduling out a task and back is far more drastic of an effect than any new events in 0.2 usecs. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
