* Ingo Molnar <mingo@xxxxxxx> [2009-02-15 11:13]: > Note that if the box you test this on is multi-core or HT, then interpreting > traces is easier if there's just a single CPU to look at. In that case i'd > suggest to reproduce with just a single core, by turning the second one off: > echo 0 > /sys/devices/system/cpu/cpu1/online > Or, if the problem only occurs with two cpus, restrict tracing to CPU#1: > echo 2 > /debug/tracing/tracing_cpumask The box I test on is HT, so I tried the first suggestion and it made the problem much less visible (but not completely absent). So I used "echo 1 > /sys/devices/system/cpu/cpu1/online" to go back to HT mode and then it made the problem much more visible on CPU#1: ksoftirqd/1 is running a lot and ksoftirqd/0 is almost normal. The load average is about 0.80 and the total running time for ksoftirqd/1 is almost one minute (and I booted on rc5 ten minutes ago)! So I followed the tracing steps in the tutorial (with the 1 sec sleep), which gave me this: http://damien.wyart.free.fr/trace_2.6.29-rc5_ksoftirqd_prob.txt.gz As I will be away until tomorrow, I did this on vanilla rc5 to get something out today, and if tip is really needed, I will work on it tomorrow. But maybe this vanilla trace will be helpful to you... Do not hesitate to ask for further tests or info. -- Damien -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
