AM335x performance with Industrial SDK

Damian Wyrobek1

Hello,

we have developed a Ethernet/IP product with the AM335 using industrial SDK. Everything is working fine at the moment but the customer is asking us for some timings which are difficult for us to measure. So i wanted to ask if somebody can provide us following informations:

1. switching delay time from one port to the other

2. processing delay for response to a DLR message

3. transparent clock jitter

I guess the ISDK team has done some measurements which could help us with the specifications

Thank you in advance and best regards

Damian

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will ask the Industrial team to comment.

0 David Zaucha over 9 years ago in reply to Biser Gatchev-XID

TI__Expert 7570 points

Hi

TI has recently released a document which contains much of the information you seek.
processors.wiki.ti.com/.../ICSS_EIP_Adapter_Developer_Guide

David

0 Damian Wyrobek1 over 9 years ago in reply to David Zaucha

Intellectual 325 points

Hi David,

thank you for your reply.

So the first point is answered but still two remain.

1. Processing of DLR frames: "DLR processing depends on frame type and state machine."

Can you give a worst case time and an average time for processing the cyclic frames of the supervisor?

2. Jitter for switching

Is there a easy way to derive the switching jitter from the oscillator ratings?

Thank you in advance and best regards

Damian

0 David Zaucha over 9 years ago in reply to Damian Wyrobek1

TI__Expert 7570 points

Hi Damian

Let me inquire on the first question.

David

0 Damian Wyrobek1 over 9 years ago in reply to David Zaucha

Intellectual 325 points

Hi David,

thank you for your reply but unfortunately I can't open your link..

Best regards,

Damian

0 David Zaucha over 9 years ago in reply to Damian Wyrobek1

TI__Expert 7570 points

Hi Damian

I apologize - I realized that a couple of updates are needed before release.
Let us have couple of days to make the updates and release.

David

0 Damian Wyrobek1 over 9 years ago in reply to David Zaucha

Intellectual 325 points

HI David,

I just wanted to know if there are some news about your mentioned page.

Best regards,

Damian

0 David Zaucha over 9 years ago in reply to Damian Wyrobek1

TI__Expert 7570 points

Hi Damian

With regard to the processing of DLR frames - The worst case time for the processing is when it will go to delayed cut-through where latency is 8-9 us.

Several new section have been added to the ICSS EIP Adapter Developer Guide. The performance measurement section is at:

http://processors.wiki.ti.com/index.php/ICSS_EIP_Adapter_Developer_Guide#Device_Performance_Testing

David

0 Damian Wyrobek1 over 9 years ago in reply to David Zaucha

Intellectual 325 points

Hi David,

thank you a lot.

But one question still is open:
Whats the jitter for the E2E transparent clock? Is there any chance for you to measure it? Or depends this value on the utilization of the A8 as I saw some PTP-code?

Best regards Damian

0 David Zaucha over 9 years ago in reply to Damian Wyrobek1

TI__Expert 7570 points

Hi Damian

The jitter for the E2E transparent clock has not yet been characterized.
The jitter is not expected to be dependent upon the A8 utilization since the transparent clock critical operations are performed by the PRU -ICSS.

David

0 Damian Wyrobek1 over 9 years ago in reply to David Zaucha

Intellectual 325 points

Hello David,

meanwhile there have been some performance testing especially with the E2E transparent clock. The jitter seems to be really high with ISDK 2.1.0.1:

- the jitter should be below 100ns

- measured jitter is about 1,3ms(max) or 13µs(avg)

Because of the big discrepancy there seems to be a problem with the code or our implementation.

Are you sure about the fact that the clock critical operations are performed by the PRU-ICSS? I have seen some ISRs (icss_ptp.c) which seems to be time critical...

Do you have any idea what to do to get a better jitter performance?

Thank you in adnvance and best regards

Damian

0 Damian Wyrobek1 over 9 years ago in reply to Damian Wyrobek1

Intellectual 325 points

Hello

are there any updates regarding the jitter issue?

Thanky you and best regards

Damian

0 David Zaucha over 9 years ago in reply to Damian Wyrobek1

TI__Expert 7570 points

Hi Damian

I apologize for the delay. We have reproduced what you are seeing - jitter in the us with intervals where it increases to the ms.. We have an update in work which is showing good improvement. Let me send you a friend request and we can discuss this directly.

David

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AM335x performance with Industrial SDK