Intel P4610 number of IRQs

[AMarin]

Hello,

I have Intel P4610 NVMe drive, using Ubuntu 20.04 with nvme kernel module.
Is it possible to change number of interrupt queues and/or assign them to different CPU cores?

If I try to enable poll mode, it simply assigns additional (poll) queues, but keeps interrupt ones as well.
If I try to change CPU core assignment for particular IRQ, sysfs does not allow it (even under 'root').

Are there any options here?


BR//Ante

[JosafathB_Intel]

Hello, AMarin.

Thank you for contacting Intel® Memory and Storage support.

As we understand, you are requesting support related to your Intel® SSD DC P4610 Series. If we inferred correctly, please, provide us with the following information:

• The system details by extracting the SSU logs.

A- Go to https://downloadcenter.intel.com/download/26735/ (for Linux) to download the software.

B- When you finish downloading it, open it.

C- Attach the file generated by the tool in your reply.

• We would like to know more about the project that you are working on and for you to further elaborate on the reason why this modification to the NVME kernel module to enable poll mode is necessary for your project.

• To check the commands and the errors you are experiencing, we would appreciate it if you may provide us with screenshots of the errors or a log file including as much information as possible.

We will follow up with you again on Monday, the 18th of April 2022, if we do not receive an answer from you. Please, let us know if you would like to schedule a different date for the follow-up.

Best regards.

Jos B.

Intel® Customer Support Technician.

[AMarin]

Hello Jos,

well, I've checked the script used to collect SSU logs, but I am not sure how helpful is it for you to know DMI table or IP configuration, in answering this question...

In any case, poll mode is not a strict target here - idea is to move IRQs from certain CPU cores so they are free to perform, uninterrupted, the latency sensitive tasks they are assigned.

So, under Ubuntu server 20.04, 5.4 kernel and nvme module being used, is it possible to change number of interrupt queues and/or assign them to different CPU cores? If it is possible, what is recommendation from Intel side on how to do it?

BR//Ante

[JosafathB_Intel]

Hello, AMarin.

Thank you for your reply.

We requested the SSU to have a better understanding of your current hardware configuration and to be able to provide a more personalized answer based on your current setup.

We are going to investigate your inquiry related to your Intel® SSD DC P4610 Series.

We will be contacting you back as soon as we have an update or if further information is required.

Best regards.

Jos B.

Intel® Customer Support Technician.

[JosafathB_Intel]

Hello, AMarin.

We appreciate your patience.

We have been working on reviewing your inquiry related to the Intel® SSD DC P4610 Series, and as you know, the SSDs/NVMe does not have interrupt queues.

An option will be to get you in contact with the team in charge of CPUs, and for this, we would like to know your PC configuration or at least your CPU model to try to assist you by redirecting your question to them.

Another option is to contact Canonical* the Ubuntu developers to see if they have a feature or an option built-in in the OS that you may be able to use for your project.

We will be looking forward to your reply, including the information about your CPU.

We will follow up with you again on Friday, the 22nd of April 2022, if we do not receive an answer from you. Please, let us know if you would like to schedule a different date for the follow-up.

Best regards.

Jos B.

Intel® Customer Support Technician.

[AMarin]

Hello Jos,

well, not sure about "not having interrupt queues" part, since I have this:
​[ 9.598701] kernel: nvme nvme0: pci function 0000:da:00.0
[ 9.612540] kernel: nvme nvme1: pci function 0000:db:00.0
[ 9.833778] kernel: nvme nvme0: 88/0/0 default/read/poll queues
[ 9.849762] kernel: nvme nvme1: 88/0/0 default/read/poll queues

cat /proc/interrupts | grep -i nvme | wc -l
178

and this is connected to number of CPU cores available on the system (2x44=88, also 2 NVMe drives). CPU model is 
cat /proc/cpuinfo | grep "model name" | head -n1
model name : Intel(R) Xeon(R) Gold 6152 CPU @ 2.10GHz


BR//Ante

[JosafathB_Intel]

Hello, AMarin.

Thank you for your reply and the information about your CPU.

The SSDs/NVMe does not have interrupt queues. The queues are controlled by the CPU or by the software that will be the OS.

We will move your thread to the Intel® Xeon CPU support for you to get further assistance related to this inquiry.

Thank you for your patience and understanding.

Best regards.

Jos B.

Intel® Customer Support Technician

[Victor_G_Intel]

Hello AMarin,

Thank you for posting on the Intel® communities.

To continue with your request please provide an answer to the following questions:

1. Are you requesting this information on behalf of a company? If yes, please provide as many details as possible about the company that you work for.
2. Can you please let us know why you need this information? Is it for some sort of a project or for something else? Please provide as many details as possible.

Regards,

Victor G.

Intel Technical Support Technician  

[Victor_G_Intel]

Hello AMarin,

We would like to know if you were able to check the previous post. 

Please let us know if you need further assistance. 

Regards,

Victor G.

Intel Technical Support Technician  

[JoseH_Intel]

Hello AMarin,

We will proceed to mark this thread as closed. If you have further issues or questions just go ahead and submit a new topic.

Regards

Jose A.

Intel Customer Support Technician