Hi! Steven Rostedt schrieb: >> it didn't get better. I still see only 2 CPUs being occupied by our test >> program. >> >> Interestingly enough, it seems I now can't use CPU2 and CPU3 at all - > > Is this also the case without PREEMPT_RT configured? Not sure if I understand your question, but let's try: When I disable CONFIG_PREEMPT_SOFTIRQS, I can use all four CPUs. >> even if I start several test processes in parallel. IIRC, this was >> better with 2.6.22.1-rt9 - there CPU2 and CPU3 got used if I started two >> test programs in parallel. >> >> I can now even reproduce the problem with a simple kernel make. Here's a >> snapshot of /proc/stat after compiling the kernel with "make -j 4": >> >> MRBOX:~/linux-2.6.23.1 # cat /proc/stat >> cpu 249482 0 46304 683034 9592 90 358 0 1 28 >> cpu0 124240 0 20690 99283 2767 50 214 0 0 8 >> cpu1 125242 0 25586 89781 6431 33 136 0 0 10 >> cpu2 0 0 8 246867 333 0 0 0 0 0 >> cpu3 0 0 18 247103 60 6 7 0 0 8 >> intr 115025 >> ctxt 8498063 >> btime 1193997310 >> processes 82614 >> procs_running 1 >> procs_blocked 0 >> >> As with 2.6.23-rt1, behaviour only breaks for me as soon as I enable >> PREEMPT_RT. > > But otherwise it runs fine (you can use CPU2 and CPU3)? Yes, as long as I don't enable CONFIG_PREEMPT_SOFTIRQS. When talking about PREEMPT_RT here, I meant it as a synonym for "all those additional config options coming with the -rt patch series". >> To narrow it down a bit, I now played a bit with the configure options >> of 2.6.23.1-rt5 (leaving PREEMPT_RT disabled and enabling the other RT >> features one after another). The culprit for me is >> CONFIG_PREEMPT_SOFTIRQS. As soon as I enable it, only CPU0 and 1 are >> used. Disabling it again makes the kernel use all CPUs. >> >> Any hint how to continue with this matter is greatly appreciated... > > Could you send me the contents of /proc/cpuinfo your dmesg on bootup > as well as the .config that you are using. Will follow in a few minutes via private mail. -- Gernot Hillier Siemens AG, CT SE 2 Corporate Competence Center Embedded Linux - 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
