i.MX6: Has someone tried PREEMPT_RT patch

[rajansrivastava]

Has someone tried PREEMPT_RT patch for Linux on i.MX6?

If yes, did you try measuring RT-latency via cyclictest -- if so, can you please share your observations?

What problem I am observing: if I use '-M' command line argument to cyclictest (that causes screen refresh only when latency is increasing), cyclictest doesn't report any latency, it just sits silent.

If I run it without '-M' option to cyclictest, I am observing latencies in order of 100s of microseconds, when there's no load at all on the CPU.

Thanks,

Rajan

[vladspiridonesc]

Hey Rajan,

Did you tried the PREEMPT_RT patch on iMX6? Which board do you have?

Regards,

Vlad

[sinanakman]

Hi Rajan, Vlad

Sometimes ago I took patches-3.14.3-rt5.tar.gz

and run it on a sabre sd board to test some

audio latencies without any problem. This was

with mainline Linux, not FSL's vendor specific

thing.

Hope this helps

Regards

Sinan Akman

[xinyu_chen]

Hi Rajan

I do not think our kernel is ready for PREEMPT_RT features. See: http://lwn.net/Articles/146861/

[rajansrivastava]

Thanks Xinyu for responding.

Do you see any explicit reason why PREEMPT_RT is not ready for our (i.MX6) kernel?

Regards,

Rajan