Hi, I tried ping as a minimal latency test, e. g. ionice -c3 -p $$ renice +19 -p $$ ping -q -s 28 -l 1 -p 0f1e2d3c4b5a6978 -i 0.001 localhost but when cyclictest shows a worst-case latency of 40 mikroseconds, ping shows more than 10,000 (after 1 day run). I tried different kernels, e. g. SMP PREEMPT RT Debian 4.6.4-1~bpo8+1 (2016-08-11) x86_64 but with the same result, low cyclictest values, high ping values. What is the reason? Regards, Rolf -- 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