On Mon, 2011-06-20 at 16:25 +0100, Jakub Nowacki wrote: > On 06/20/2011 04:02 PM, Gilles Chanteperdrix wrote: > > To make proper benchmarks, you should: > > - let the latency run long > > - provide some load, you can use the dohell script in xenomai-head to > > generate the load. > > > I've generated a load using 'dd if=/dev/zero of=/dev/null' one for each > core (8 in total), which is roughly the way how xeno-test does it. The > test was running for 30 min, which is not very long but I should see the > long latencies by that time, I think at least. > > > That said, having some spikes is not abnormal. The real question is to > > know whether the latencies your get are sufficient for your application. > > > Well, I think it should be OK for peak latencies < 20 us, that is what > I'm getting now. > > >> ioctl(RTTST_RTIOC_SWTEST_CREATE_KTASK): Cannot allocate memory > > > > You have to increase CONFIG_XENO_OPT_SYS_STACKPOOLSZ. > > > It is 128 Kb now. Should it be more? Is there any (thumb) rule for this > value?
Max # of concurrent kernel-based Xenomai threads x stack_size. 8k stack minimum is a safe bet for x86_64. Typically, RTDM (driver) tasks in kernel space are Xenomai ones, so you would need to reserve stack space for each of them in this amount. The switchtest driver is RTDM-based, and may run a number of RTDM tasks, depending on the test scenario. > > Best wishes, > > Jakub > > _______________________________________________ > Xenomai-help mailing list > [email protected] > https://mail.gna.org/listinfo/xenomai-help -- Philippe. _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
