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C6457 and JUMBO frames

sergey manuhin
Intellectual 710 points

Hi

I work with the board c6457 from Lyrtech and I have a problem with Jumbo frames.

 I have to send a real time video through Ethernet by UDP. To do this I have installed NDK 2 and NSP for c6457. To reduce CPU load I want to use JUMBO frames.

I have included define _INCLUDE_JUMBOFRAME_SUPPORT.

Then, I have created my own function for testing net.

There is an unexpected result.  When I use Jumbo  the load of my c6457 is 60%. When I don’t use JUMBO  the load of my CPU is 60% too.

I think that JUMBO frames don't  work properly.

In ethdriver.c  file  in the NSP 6457 you can see that MTU=1500. It is incorrect for Jumbo.

It is written in  ethdriver.c  file in the NSP 6455  if I use Jumbo frames  MTU =10000.

Why is it written for the c6457,that MTU=1500?

I have set MTU=10000 in this file manually and rebuilt it.

But when connecting the ETH  error is occurred.

How can I include JUMBO frames or set MTU = 10000?

 

  • 0
    TI__Intellectual 1880 points

    Sergey,

    I am have not used the NDK software much, but I do not believe that jumbo packets are supported by the hardware. The maximum packet length supported by the 6457 Ethernet MAC module is 1518 bytes.

    For more information, please refer to the C6457 EMAC/MDIO user guide (http://focus.ti.com/lit/ug/sprugk9/sprugk9.pdf). If you search for RXMAXLEN, then you can see that the maximum size is 1518 bytes.

    Regards,

    Derek

  • 0 in reply to Derek Brown
    Intellectual 710 points

    So far as I understand, the processor c6457 doesn’t support JUMBO frames? Am I right?
    But In the NSP for the c6457 is written that using RAW socket, you can get the following result:
    Board        Data rate    CPU loading
    EVM6457    781Mb/s       10%

    I have implemented data transfer using a RAW sockets but CPU load is still at 60%.
    How can I achieve the CPU load of 10%? Do you have any examples to  get the results like in documentations in NSP?