[Starlingx-discuss] Question - Using 1Gb mem pages

[Rowsell, Brent]

If you want to use 1G huge pages, you need to provision 1G huge  pages in sysinv for the compute and then specify the page size extra spec when launching the VM.

system  host-memory-modify
usage: system host-memory-modify [-m <Platform Reserved MiB>]
                                 [-2M <2M hugepages number>]
                                 [-1G <1G hugepages number>]
                                 <hostname or id> <processor>

You will have to reduce the number of 2M huge pages to accommodate the 1G requirements.
You should not be manually modifying grub args.

Brent

From: Perez, Ricardo O [mailto:ricardo.o.perez at intel.com]
Sent: Friday, October 19, 2018 1:45 PM
To: starlingx-discuss at lists.starlingx.io
Subject: [Starlingx-discuss] Question - Using 1Gb mem pages

Hello,

I'm trying to execute a test, which his goal is to made use of huge pages (2M / 1G) launching a VM.

I have already verified the configuration of the controllers GRUB options and we have defined the variable hugepagesz=1G, however, inside the same parameters list, there is a "default_hugepagesz=2M". The default hugepagesz, has been modified to 1G, and the compute has been restarted with no issues.

The flavor has been modified, with the following option: " hw:mem_page_size=104875"  (1G) page.

However when I launch a VM using the modified flavor it creates the VM, but if I check the field values of the VM using " openstack server show <vm_name>". I'm getting the following value for pgsize:
wrs-res:topology                    | node:0,   512MB, pgsize:2M, vcpus:0, pol:sha |

So, seems like it's still taking the 2M pagesize instead of the 1G.

What I have already tried is to:

*         Change also the image metadata: hw:mem_page_size=large and also 104875. Result, VM launched successfully, but pgsize value still 2M.

*         Leave the GRUB default values, and use modified flavor to hw:mem_page_size=104875, launch the VM with ERROR status.

*         Leave the GRUB default values, and use modified flavor to hw:mem_page_size=2048, launch the VM with success, , pgsize value is 2M, which is expected, ok.

*         Leave the GRUB default values, and use modified flavor to hw:mem_page_size=small launch the VM with success, , pgsize value is 4k, which is  expected, ok.

*         Leave the GRUB default values, and use modified flavor to hw:mem_page_size=any launch the VM with success, , pgsize value is 2M, which is  expected, ok.

Could be this an issue trying to use 1G mem pages or do I'm missing some other configuration parameter?

Thanks in advance for your help
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