On 1/12/2014 2:56 PM, Gilles Chanteperdrix wrote: > On 01/11/2014 09:58 PM, Charles Steinkuehler wrote: >> (Starting a new thread) >> On 1/7/2014 5:13 PM, Gilles Chanteperdrix wrote: >>> On 01/07/2014 11:55 PM, Charles Steinkuehler wrote: >>>> On 1/7/2014 4:47 PM, Gilles Chanteperdrix wrote: >>>>> Is there any chance you could trigger a trace with the I-pipe >>>>> tracer? >>> >>>> I can try...give me a while to sort through the I-pipe:Tracer wiki >>>> page (or are there better instructions?). >>> >>> Enable I-pipe tracer in kernel configuration, especially >>> IPIPE_TRACE_MCOUNT, and IPIPE_TRACE_VMALLOC. >>> >>> When the system has booted, do: >>> >>> echo 1 > /proc/ipipe/trace/enable >>> echo 1000 > /proc/ipipe/trace/back_trace_points >>> >>> Then launch latency -p 200 -f >>> >>> Run the load you usually run (for instance dohell). >>> >>> When the test is finished, do >>> cat /proc/ipipe/trace/frozen > /tmp/frozen.txt >>> >>> then post the resulting frozen.txt to this list. >>> >>> Expect the latency found by the test to be double the latency you get >>> without the I-pipe tracer. >> >> OK, I tested a variety of kernels. Simply enabling the ipipe trace >> options on the otherwise unchanged kernel configuration I'm using >> resulted in a system that was *EXTREMELY* slow and unresponsive, even >> before I enabled the iPipe trace. After waiting the better part of a >> day for a GUI application to launch, I gave up on this kernel and tested >> one with the recommended performance options: >> >> >> Already in the BeagleBone Xenomai kernels I've been building: >>> optimize for size >>> disable CONFIG_PREEMPT >>> enable stack unwinding >>> disable root thread priority coupling (xenomai option) > > The .config you attached to the mail I am answering has CONFIG_PREEMPT > enabled. > You may want to select CONFIG_PREEMPT_NONE.
OK, thanks for the clarification. I show CONFIG_PREEMPT was not set, but CONFIG_PREEMPT_VOLUNTARY was: # CONFIG_PREEMPT_NONE is not set CONFIG_PREEMPT_VOLUNTARY=y # CONFIG_PREEMPT is not set I can select CONFIG_PREEMPT_NONE and re-test. > I also do not really understand the trace you have attached. Are you > running other real-time tasks than the latency test? Because to get > accurate results, you should run the latency test without any other > programs using xenomai. Yes, my primary load is running LinuxCNC, which uses Xenomai. I'll build a new kernel and post a new trace, this time without running any other programs that use Xenomai. Thanks for all the advice and help! -- Charles Steinkuehler [email protected] -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 261 bytes Desc: OpenPGP digital signature URL: <http://www.xenomai.org/pipermail/xenomai/attachments/20140112/bbf3cd16/attachment.sig> _______________________________________________ Xenomai mailing list [email protected] http://www.xenomai.org/mailman/listinfo/xenomai
