On Tuesday 27 May 2014 18:38:33 Stanislav Meduna wrote: > On 26.05.2014 11:26, Arnd Bergmann wrote: > > > It seems like the right thing to do, I just don't understand > > why nobody hit this before. > > Looks like this is what I did hit a month ago and > was not able to find the culprit: > http://www.spinics.net/lists/linux-rt-users/msg11656.html Ok, so you get a 2.2ms latency on i.mx28 here, which comes from exactly the same code location, and is quite alarming by itself, but much less so than the 4 second latency that Corey is seeing. This could just be an artifact of i.mx28 not staying idle for as long as vexpress. > > How exactly do you see this manifest? If it's clear > > that the trace comes from the idle function, maybe > > everybody just ignores it? > > That was definitely what I did You also commented in that thread about stop_critical_timings()/ start_critical_timings(). Corey, can you look at that, too? I think it's designed to avoid the issue you are seeing but for some reason doesn't. Maybe the problem is that the tracing infrastructure gets confused when the irq_disable() happens in a different function from irq_enable(). Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
