On Thu, Aug 25, 2011 at 11:03:33PM +0200, Christian Kraus wrote: > Hello > I have wrote a GPIO-driver, that toggle the value of a GPIO when a > interrupt is comming from an another GPIO. > When I measure the latency between the interrupt and the toggled Pin > it's about ten times higher than without the rt-patch. > (without Patch = 8-11 us > with Patch = 30-110 us) It's expected and known that an rt kernel has a worse average latency. Having said that I cannot say if the increase you see is "too much". The best option you have is asking ftrace what happens in these 30-110 us after making sure you have a decent sched_clock implementation. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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
