Real Time Linux on iMX28

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Real Time Linux on iMX28

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tty
Contributor I
Anyone made the i.mx28 Linux kernel a real time?
Regards.
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awdenx
Contributor II
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fabio_estevam
NXP Employee
NXP Employee

I am not familiar with the cyclictest, but maybe one element that can explain the better performane on MX27 is due to the 32bit DDR interface versus 16bit DDR on MX28.

 

Regards,

 

Fabio Estevam

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tty
Contributor I

Thanks, Fabio.

I tried a 3.0.4 kernel with a patch-3.0.4-rt14. But I got bad results, I think. Cyclictests result:

/usr/local/bin/cyclictest -a -n -m -p99
policy: fifo: loadavg: 15.67 16.92 15.62 18/69 4270
                                                                                                                                                                                                                                                 
T: 0 ( 8894) P:99 I:1000 C:2209243 Min:     31 Act:  125 Avg:  115 Max:     656

/usr/local/bin/cyclictest -a -n -m -p99


This test has much better result on imx27(https://www.osadl.org/Latency-plot-of-system-in-rack-2-slot.qa-latencyplot-r2s1.0.html), but with 2.6.33 kernel.

 

Fabio Estevam said:

Real Time patches are available at:

http://www.kernel.org/pub/linux/kernel/projects/rt/

 

MX28EVK is supported in the mainline kernel, so you can try it running RT on a 3.0 kernel.

 

Regards,

 

Fabio Estevam

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cono
Contributor I

Hi,

the timer initialization used by iMX28 is not correct as discussed here:

http://list-archives.org/2012/12/21/linux-kernel-vger-kernel-org/improve-timer-resolution-on-imx28/f...

With this fix I got worsed case latency times about 210us.

Regards

Christoph

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fabio_estevam
NXP Employee
NXP Employee

Real Time patches are available at:

http://www.kernel.org/pub/linux/kernel/projects/rt/

 

MX28EVK is supported in the mainline kernel, so you can try it running RT on a 3.0 kernel.

 

Regards,

 

Fabio Estevam

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