[LITMUS^RT] Installing LITMUS RT on Odroid XU4

[Björn Brandenburg]

> On 20. May 2019, at 18:35, sobhan niknam <sobhan.niknam at yahoo.com> wrote:
> 
> 
> 
>> On 20 May 2019, at 17:40, Björn Brandenburg <bbb at mpi-sws.org> wrote:
>> 
>> On 20. May 2019, at 16:40, sobhan niknam <sobhan.niknam at yahoo.com> wrote:
>>> 
>>> There is no log file in /dev/litmus to look at.
>> 
>> I’m not talking about a LITMUS^RT-specific device file. Check the standard kernel log. 
> 
> The buffers overflowed: 
> 
> May 21 01:12:37 odroid kernel: [341828.508325] [c1] Failed trace writes: 25486
> May 21 01:12:37 odroid kernel: [341828.508344] [c3] Failed trace writes: 46617
> May 21 01:12:37 odroid kernel: [341828.508364] [c0] Failed trace writes: 19335
> May 21 01:12:37 odroid kernel: [341828.508381] [c2] Failed trace writes: 0
> May 21 01:12:37 odroid kernel: [341828.508619] [c2] Failed trace writes: 6915121
> May 21 01:12:37 odroid kernel: [341828.508627] [c0] Failed trace writes: 6713421
> May 21 01:12:37 odroid kernel: [341828.508696] [c3] Failed trace writes: 23201
> May 21 01:12:37 odroid kernel: [341828.511328] [c3] Failed trace writes: 7169319

Makes sense. If you have gaps in the record, then of course the resulting traces will be incomplete and/or strange. 

> 
>>> However, what should I do if supposing the trace buffers overflowed?
>> 
>> If you have enough memory, increase the trace buffer size. Otherwise, make sure they get drained quickly enough. 
> 
> 
> I increased the buffer size of each cpu core in /sys/kernel/debug/buffer_size_kb, but the problem still exists!

I’m not sure how you hit on that setting, but I don’t think it has anything to do with LITMUS^RT. The LITMUS^RT trace buffers are configured statically via .config. 

- Björn