Hi Matthias > without hackbench and frieds (idle system) I get a max. latency of about > 4ms. Running hackbench (default arguments, -l 1000), it still increases up > to 5ms: > > ... > # Total: 000000193 > # Min Latencies: 00024 > # Avg Latencies: 00205 > # Max Latencies: 05058 > ... > > The obvious PM stuff is disabled. No dynamic frequency scaling, etc. > Really weired stuff. I already mentioned the 3.2 system with the same CPU in > the OSADL lab. It comes with max. latency of 118us. So I really expect > something similiar. Yeah 118 µs should be the right ballpark, while still a little high for my taste. All cortex a8 seem to have rather high latency. The A9's seem much better in this respect. Have you seen the following: https://www.osadl.org/Realtime-Preempt-Kernel.kernel-rt.0.html#latencyfighting Cyclictest has tracing support which might help finding the cause of the long latency. Best regards Tim -- 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
