DRA829J: Missing RX interrupts from CPSW9G

Matthias Hörger

Part Number: DRA829J

Tool/software:

Hi,

We use CPSW9G in native ethernet configuration. We have cyclic RX traffic every 1ms. From time to time we experience missing RX interrupts for 2.5ms.

According to this thread PROCESSOR-SDK-J784S4: FreeRTOS enet examples enet_loopback_test 5ms Freeze every 2-5 million send frames - Processors forum - Processors - TI E2E support forums, a statistics counter overflow can cause this kind of delay.

Is this also true in the native ethernet configuration? How can we test this (can we disable the counters?)?

Regards,

Matthias

1 month ago

+1 Tanmay Patil 1 month ago

TI__Mastermind 31170 points

Hi Matthias,

In native linux context, this is not the case. The statistics are not saved in counters in software. They are read from hardware anytime that is needed.

How are you checking the missing Rx interupts?

Regards,
Tanmay

0 Matthias Hörger 1 month ago in reply to Tanmay Patil

Prodigy 55 points

Hi Tanmay,

We use Linux preempt_rt with every interrupt having a corresponding RT kernel thread. With kernel shark we can observe the "irq/138-c000000.ethernet" kernel thread not doing anything for 2ms.

Regards,

Matthias

0 Tanmay Patil 1 month ago in reply to Matthias Hörger

TI__Mastermind 31170 points

Hi Matthias,

This is a weird observation.

What is the CPU utilization during this time? What are the tasks running during this time.

Does upping the priority of the irq thread makes this issue less unlikely?

Regards,
Tanmay

0 Matthias Hörger 1 month ago in reply to Tanmay Patil

Prodigy 55 points

Hi Tanmay,

There is almost no CPU utilization. As we just started our investigation, I can't tell you much more at the moment. I guess your previous post answered my original question. I will open a new topic, if we have more data.

Regards,

Matthias