PROCESSOR-SDK-AM62X: PSDK-RTLINUX Performance Test using cyclictest on top of PSDK RT-LINUX

Jack

Hi TI

The customer ran the cyclictest program to check the performance of the RT Linux SDK,
A 1 ms control cycle is required to control the robot, and the stress test was conducted with Core3 assigned as a separate process.

If there is no load, there is no problem even if it is operated for more than 8 hours,
If you apply stress, the delay time is longer in about 20 minutes, causing problems.
I would like to ask if there is a separate test method or a solution to the delay time so that the tasks assigned to CORE3 do not cause delay time.

I am attaching their test procedures and results.
Please give me some advice.

latency-en.pdf

Thanks.

Regards,

Jack

over 2 years ago

0 Praneeth Bajjuri over 2 years ago

TI__Expert 6596 points

The recommended test details are captured in release notes

https://software-dl.ti.com/processor-sdk-linux-rt/esd/AM62X/09_00_00_03/exports/docs/devices/AM62X/linux/RT_Linux_Performance_Guide.html#stress-ng-and-cyclic-test

0 Jack over 2 years ago in reply to Praneeth Bajjuri

Mastermind 9926 points

Hi Praneeth

Can you please check if the Core3' latency could be reduced less than 20us even under heavy stress conditions?

Customer need the improvement of realtime scheduling of Core 3 even under stress load.

Thanks.

Regards,

Jack

0 Schuyler Patton over 2 years ago in reply to Jack

TI__Mastermind 41330 points

Hi Jack,

In the release notes is the best latency measured so far. 20uS is not realistic on this processor.

Best Regards,

Schuyler

0 Pekka Varis over 2 years ago in reply to Schuyler Patton

TI__Mastermind 27050 points

20us is not realistic for A53.

Your results are 8.6. With 9.0 SDK this is what we get are in https://software-dl.ti.com/processor-sdk-linux-rt/esd/AM62X/09_00_00_03/exports/docs/devices/AM62X/linux/RT_Linux_Performance_Guide.html#stress-ng-and-cyclic-test . Here is some further runs:

root@am62xx-evm:~# stress-ng -c4 --cpu-method=all &
root@am62xx-evm:~# cyclictest -m -Sp98 -i1000 -h800 -l100000000 -q > output

# Max Latencies: 00104 00108 00128 00103

Further improvement with kernel option CONFIG_ARM_ARCH_TIMER_EVTSTREAM=n

root@am62xx-evm:~# stress-ng -c4 --cpu-method=all &
root@am62xx-evm:~# cyclictest -m -Sp98 -i200 -h800 -l100000000 -q > output

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PROCESSOR-SDK-AM62X: PSDK-RTLINUX Performance Test using cyclictest on top of PSDK RT-LINUX