Server Products
Data Center Products including boards, integrated systems, Intel® Xeon® Processors, RAID Storage, and Intel® Xeon® Processors
5015 Discussions

PCIe multicast capability

shouxu
Beginner
59,873 Views

We want to seek clarification regarding the PCIe multicast capability (Page 888, https://kolegite.com/EE_library/books_and_lectures/%D0%A6%D0%B8%D1%84%D1%80%D0%BE%D0%B2%D0%B0%20%D1%81%D1%85%D0%B5%D0%BC%D0%BE%D1%82%D0%B5%D1%85%D0%BD%D0%B8%D0%BA%D0%B0/%D0%B8%D0%BD%D1%82%D0%B5%D1%80%D1%84%D0%B5%D0%B9%D1%81%D0%B8/Mike%20Jackson%2C%20Ravi%20Budruk%2C%20Joseph%20Winkles%2C%20Don%20Anderson%20-%20PCI%20Express%20Technology%203.0-MindS...) and its configuration on our Intel servers (R840 and R750). In particular, we are trying to enable PCIe multicast in a simple topology where multiple PCIe devices are directly attached to the root complex. The following are detailed questions in this context:

1. Checking Multicast Support:
Does the PCIe root complex on our servers support the multicast capability, and if yes, how do we enable/configure it? Online references seem to indicate that Intel root complexes support this feature (https://forums.developer.nvidia.com/t/orin-and-pcie-multicast/259583). Additionally, how do we check if an attached PCIe device is compatible with PCIe multicast?
We tried to enable multicast by setting the MC_ENABLE bit in the Multicast Control Register (offset 0x336) using the setpci command. The value gets updated on the PCIe root port, however, it does not for the PCIe device. Is this an indication that the specific device does not support multicast? Moreover, for the root port, even though the bit is set, no multicast-related details are displayed by lspci.

2. MC_Base_Address Configuration:
We are unclear about the configuration of MC_Base_Address. Is this address located within the Base Address Register (BAR) of the device, or is it located elsewhere in the memory space? When we tried to read the value of the MC_Base_Address from the root port, it returns 0, and we are unable to update the value.

3. Group Window Values:
Regarding the values to be placed in each group window, are these simply the BAR addresses of the target functions of each device within the multicast group? What determines the set of devices that constitute each multicast group?

If possible, could you provide a concrete example demonstrating how to set up the multicast capability registers on a simple PCIe topology? This would greatly help us visualize the process. Pointers to any additional documentation related to PCIe multicast would also be helpful.

0 Kudos
3 Replies
IntelSupport
Community Manager
59,835 Views

Hello shouxu,


Greetings for the day!

 

This is regarding the case you have with us with the following details.

Case Number: 06009835

Problem: PCIe multicast capability

 

Could you please provide the details of the server you are using?

 

Please feel free to reach out to us if you require any further assistance or have additional questions. We appreciate your continued use of Intel products and services.

 

Best regards,

Vijay N

Intel Customer Support.

 


0 Kudos
IntelSupport
Community Manager
59,784 Views

Hello shouxu,


Thank you for contacting Intel Customer Support and this is the case number 06009835 for your references.


We hope this message finds you well. We are sending a follow up if you have any questions from the previous post. If so, please let us know.


Please don’t hesitate to contact us for any further assistance.

Thank you for using Intel products and services.

 

Best Regards,

Vijay N

Intel customer Support.


0 Kudos
IntelSupport
Community Manager
59,752 Views

Hello shouxu,


Greetings for the day!


We would like to inform you that we are closing this request as no response has been received from our previous follow-ups. Please don't hesitate to ask any further questions in the future. Feel free to start a new conversation, as this thread will no longer be monitored.


Best regards,

Vijay N



0 Kudos
Reply