locked
Conservative RSS Profile assigns 2 CPUs when 1 RSS Queue is chosen RRS feed

  • Question

  • Hi,

    I'm trying to understand how RSS works and while experimenting, I found out that when Convervative RSS Profile is used with 1 RSS Queue, Indirection Table stay the same, with two processors. Is that correct behavior?

    I'm asking, because when I choose other RSS Profile (for example Closest or ClosestStatic), number of the processors in IndirectionTable always match NumberOfReceiveQueues.

    Is that mean that I have some bad version of Powershell/Windows/Drivers or is it correct??

    Can anyone help with that?

    I've used Set-NetAdapterRss cmdlet to set things up.

    Name : test_port
    InterfaceDescription : Intel(R) Ethernet Server Adapter I350-T4 #2
    Enabled : True
    NumberOfReceiveQueues : 1
    Profile : Conservative
    BaseProcessor: [Group:Number] : 0:0
    MaxProcessor: [Group:Number] : 0:26
    MaxProcessors : 14
    RssProcessorArray: [Group:Number/NUMA Distance] : 0:0/0 0:2/0 0:4/0 0:6/0 0:8/0 0:10/0 0:12/0 0:14/0 0:16/0 0:18/0 0:20/0 0:22/0 0:24/0 0:26/0
    IndirectionTable: [Group:Number] : 0:0 0:2 0:0 0:2 0:0 0:2 0:0 0:2
    ...

    Friday, March 13, 2020 12:39 PM

Answers

  • Hi,

     

     

    >>Is it correct for Conservative RSS Profile to show IndirectionTable with 2 CPU even that only 1 RSS Queue is set?

     

    Based on my knowledge, the Indirect Table with the two processors is normal.

     

    Hope this can help you, if you have anything unclear, please let me know.

    Have a nice day!

    Ellen


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, March 19, 2020 7:15 AM

All replies

  • Hi,

    >>I found out that when Convervative RSS Profile is used with 1 RSS Queue, Indirection Table stay the same, with two processors. Is that correct behavior?

     

    The commend : Set-NetAdapterRss is used to change number of RSS queues.

    You can use the commend: Get-NetAdapterRss to check RSS status.

     

    Please refer the following link for more details:

     

    https://www.broadcom.com/support/knowledgebase/1211161326328/rss-and-vmq-tuning-on-windows-servers

     

    Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information

     

    The Indirect Table with the two processors is normal.

     

     


     

    A NIC uses a hashing function to compute a hash value over a defined area (hash type) within the received network data. The defined area can be noncontiguous.

    A number of least significant bits (LSBs) of the hash value are used to index an indirection table. The values in the indirection table are used to assign the received data to a CPU. 

    You can refer the following link for more information:

     

    https://docs.microsoft.com/en-us/windows-hardware/drivers/network/introduction-to-receive-side-scaling

     

     

    Hope this can help you, if you have anything unclear, please let me know.

    Have a nice day!

    Ellen

     

     

     

     


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, March 16, 2020 9:18 AM
  • Hi,

    Just checking in to see if the information provided was helpful.

    Please let us know if you would like further assistance.

    Best Regards,

    Ellen


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, March 17, 2020 6:09 AM
  • Hi,

    Thanks for answer and links with useful knowledge. Although, my question is why when I use different RSS Profile with 1 RSS Queue i get IndirectionTable with 1 CPU and with Conservative profile, it always shows two processors regardles of number of RSS Queues setting.

    Question is:

    Is it correct for Conservative RSS Profile to show IndirectionTable with 2 CPU even that only 1 RSS Queue is set?

    Wednesday, March 18, 2020 10:52 AM
  • Hi,

     

     

    >>Is it correct for Conservative RSS Profile to show IndirectionTable with 2 CPU even that only 1 RSS Queue is set?

     

    Based on my knowledge, the Indirect Table with the two processors is normal.

     

    Hope this can help you, if you have anything unclear, please let me know.

    Have a nice day!

    Ellen


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, March 19, 2020 7:15 AM