About RSS function of ixgben

[MASATOSHI_T]

I am using ESXi6.7Update3

I enabled the RSS function of the driver by using the following command.

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esxcli system module parameters set -m ixgben -p "RSS=1,1,1,1,1,1,1,1"

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After enabling the function, when checking the output result with the following command, there was a difference in the output result from ESXi for which the RSS function was enabled in the past.

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vsish -e cat /net/pNics/vmnic0/rxqueues/info rx queues info {
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Output result of ESXi enabled this time "ixgben  1.8.7-1OEM.670.0.0.8169922"

　  Rx Queue features:features: 0x482 -> Pair Dynamic GenericRSS

Output result of ESXi enabled in the past "ixgben 1.7.20-1OEM.670.0.0.8169922"

      Rx Queue features:features: 0xa4 -> RSS DynamicRSS Dynamic

The type of RSS enabled is different. Is this the difference in the name depending on the driver version?

In that case, are they equivalent in function?

When I contacted VMware, I was asked to contact the hardware vendor, so I asked a question.

[Zigfreid_Intel]

Hello MASATOSHI_T,

Firstly we do apologize for the delay in providing you an update since the case was being further checked by our engineers. 

As per advised by our engineers, this would be the answer to your question;

ESXi CLI command:

      vsish -e cat /net/pNics/vmnic0/rxqueues/info

Answer regarding the outputs (below line items): 

 Rx Queue features:features: 0x482 -> Pair Dynamic GenericRSS

  Rx Queue features:features: 0xa4 -> RSS DynamicRSS Dynamic

The "Rx Queue features:features:" is some bitmap field indicating what Rx features are enabled.

Basically, every "bit" in that hexadecimal value indicates what features are enabled or not.

The strings that say "Pair Dynamic GenericRSS" or "RSS DynamicRSS Dynamic" are translating the bitmap field to indicate what features are enabled.

For reference, please see section:

8.5.4 Checking whether RSS is enabled" of "NSX-T Reference Design Guide 3-0"

https://nsx.techzone.vmware.com/resource/nsx-t-reference-design-guide-3-0#_Toc12811581

In the guide, it details steps to obtain the "info" for "rxqueues". See below:

Example 1:

Use the “vsish” command to check whether RSS is enabled. The following example shows how to check whether RSS (marked blue) is enabled on NIC vmnic (marked in red).

[Host-1] # vsish

/> get /net/pNics/vmnic0/rxqueues/info

rx queues info {

# queues supported:5

# filters supported:126

# active filters:0

Rx Queue features:features: 0x1a0 -> Dynamic RSS Dynamic Preemptible

}

Example 2:

Further in section "8.5.6  Checking whether Rx Filters are enabled", we see a different example:

[Host-1] vsish

/> cat /net/pNics/vmnic5/rxqueues/info

rx queues info {

 # queues supported:8

 # filters supported:512

 # active filters:0

 # filters moved by load balancer:254

 # of Geneve OAM filters:2

 RX filter classes:Rx filter class: 0x1c -> VLAN_MAC VXLAN Geneve GenericEncap

 Rx Queue features:features: 0x82 -> Pair Dynamic

}

Note: Based on these entries, we can assume that the bits translate to the following:

0x482 (Pair Dynamic GenericRSS) - 0x082 (Pair Dynamic) = 0x400 => GenericRSS

0x400 => GenericRSS

0x1a0 (Dynamic RSS Dynamic Preemptible) and 0x082 (Pair Dynamic) seems to have a bit in common (0x080).

It's assumed it's related to "Dynamic"

Thus, we can deduce:

0x080 => Dynamic

0x002 => Pair

Since both 0x1a0 (Dynamic RSS Dynamic Preemptible) and 0xa4 (RSS DynamicRSS Dynamic) has "Dynamic" in it, we can substract "Dynamic" and "0x080" from both of them:

0x120 (Dynamic RSS Preemptible) and 0x024 (RSS DynamicRSS).

The remaining bit common to both of the above which is 0x020 and it would seem to map to Dynamic RSS:

0x020 => Dynamic RSS

Thus, the remaining bits map to the following:

0x004 => RSS

0x100 => Preemptible

If you have questions or other clarifications please let us know so we can help you further.

Awaiting to hear from you soon, should there be no response from you, I’ll make sure to reach out after 3 business days. Thank you and have a nice day!

Best regards,

Zigfreid I.

Intel® Customer Support

[MASATOSHI_T]

Hello Zigfreid_Intel

Thank you for your answer.

In other words, what they both have in common is dynamic RSS

solved.
Thank you very much.

[Zigfreid_Intel]

Hello MASATOSHI_T,

Thank you very much for your patience for waiting on our updates and we are glad that we are able to answer your concern. We would also like to ask if you have other questions or concerns so we would know if we can already close the thread, please advise us. 

Hoping to hear from you soon.

Should there be no response from you, I’ll make sure to reach out after 3 business days

Best regards,

Zigfreid I.

Intel® Customer Support