SRIO maximum payload

Hi Oleg,

if you want to transfer 1MB data, you will need to allocate enough heap to cover the buffers size.

please refer the below link, it should be help full for you.

http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/p/125626/454417.aspx#454417

Thanks,

Dear Ganapathi Dhandapani!

I've read the post you've linked. As I understand, I can set SRIO_MAX_MTU definition to 1 MB to allocate buffers with this size, but I should set SRIO_TYPE9_MESSAGE_SIZE definition to 64kB (but not larger) to use it in Srio_sockSend() function. So I should use some cycles to send 1MB buffer per 64kB packets.

Am I right?

And another question: should I split 1MB data buffer into 64kB chunks by myself in software or it'll be done automatically by hardware? And what about DirectIO mode which is able to transfer up to 1MB by hardware?

Hi Oleg,

Your understanding is correct, No need to split 1MB data buffer into 64KB, SRIO LLD will take care. DirectIO mode will support to transfer up to 1MB.

Refer below SRIO training link for more information

http://learningmedia.ti.com/public/HPMP/KeyStone/11_SRIO/Index.html

http://learningmedia.ti.com/public/HPMP/KeyStone/index.html

Thanks,

Dear Ganapathi Dhandapani!

1. Data payload with length more than 64kB isn't received when using TYPE9 messages - Srio_rxCompletionIsr() isn't called. 64kB is the maximum data payload I've worked well with.

2. SRIO LLD doesn't split data payload more than 64kB into chunks, it doesn't check data payload size, so my question is the same - data splitting will be done automatically by hardware or I should do it by myself?

Hi Oleg,

The 1 MB payload limit is for direct I/O operations, which use other packet types and are handled by the LSUs.

The maximum size per LSU transfer block is 1MB, if transfer->byteCount larger than 1MB, this function only submit transfer for 1MB. After transfer submission, the transfer->byteCount is decreased to indicate the remaining bytes, the transfer addresses are increased to indicate the start address for next possible transfer. The caller can check these to take proper action.Transaction ID and context bit are recorded in transfer->transactionID and transfer->contextBit for caller to check completion status.

If you need more information, 6433.SRIO_Programming_Performance.pdf Refer section 3 "SRIO transfer programming" in attached document.

Thanks,

Hi Ganapathi Dhandapani!

My questions are about TYPE9 messages, I'd like to use them to transfer large payloads such as 1 MB.

Hi Oleg,

SRIO Type 9 does not support transmit message length more than 64KB.

Note: Type 9 It should be noted that the transmit message length field cannot exceed 64KB. The priority, CRF, VC information for the transaction is received from RIO_TX_Queue_Scheduler_Info[1-4] registers. The destination port is also based on the RIO_TX_Queue_Scheduler_Info[1-4] registers. The segment size is based on the MTU field of the CAR register. The minimum payload can be 1 byte; however it is padded in that case, to make the minimum PDU of one double word. The length of the entire payload is sent by the PKTDMA before sending the payload itself.

yes, data splitting will be done automatically by hardware.

Thanks,

Hi Ganapathi Dhandapani!

I don't understand you, please, tell me again: does C6678 hardware split messages with length more than 64 kB when using SRIO TYPE9 messages?