Carsten Emde wrote: > Does the attached patch help? Sorry for the late reply. I now switched to linux-2.6.29.6-rt23 (which has the patch included) and verified that the problem is solved. Reverting the patch gives the problem again. Now the error messages have disappeared, but I really cannot tell if the test is doing something at all. Here's the output from running the python script from rt-tests-50: $> hwlatdetect --debug debugging prints turned on looking for modules module path: /lib/modules/2.6.29.6-rt23-pae-debug/kernel/drivers/misc checking /lib/modules/2.6.29.6-rt23-pae-debug/kernel/drivers/misc/hwlat_detector.ko not mounting debugfs test duration is 120s hwlatdetect: test duration 120 seconds parameters: Latency threshold: 10us Sample window: 1000000us Sample width: 500000us Non-sampling period: 500000us Output File: None Starting test Starting hardware latency detection for 120 seconds enabling detector module first attempt at enable detector module enabled disabling detector module first attempt at disable detector module disabled Hardware latency detection done (0 samples) test finished Max Latency: 0us Samples recorded: 0 Samples exceeding threshold: 0 not umounting debugfs The output from the hwlat_detector module is: hwlat_detector: version 1.0.0 For me, the output "Samples recorded: 0" means that no samples have been read at all. Or do I misinterpret the output? It is also not possible for me to cat the sample entry when the module is enabled: "strace cat sample" just waits forever: open("sample", O_RDONLY|O_LARGEFILE) = 3 fstat64(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 read(3, Is there anything else I can try? Best regards, W. Steinwender -- 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