Use persistent memory as RAM - Kernel 5.1 new function


I read that with kernel 5.1 a new function was introduced to use persistent memory as RAM (Link).
So I have some questions, is it already usable, what I doubt. Or how can I find information about the development? I assume there is still development required to make it usable.
It is also mentioned to use NVDIMM. What kind of memory is this? Intel optane? and then is it usable with AMD?

I know this post is bit mixed up, because I only found during release of 5.1 some small notes about it. I would like to use this technology later as cheap main memory for machine learning.


NVDIMM is persistent memory, that provides persistence for data stored in DRAM. That means the module can permanently store the data in DRAM even after an unexpected power loss. It’s seen in the enterprise world.

I guess that means the optane dimms are almost ready to launch

The point is you could use these storage as RAM, not for the swap partition/file. This would be interesting for use cases where you need a lot of RAM but slower access times are ok.

However I don’t know if it’s working out of the box, this would be my question how to set it up.

NVDIMMS and Optane are very different creatures… memory architecture wise… While the follow the same pinout per JEDEC standard the architectures are different… Pure DRAM based NVDIMM will be slower than optane because optane is 3D memory technology. before it was overglorified lets talk about what it was. Since its built in my area… Boise Idaho… the Home of micron… Micron built it with a codeveloped research endeavor with intel… They hate giving much credit to intel which they should as intel did a ton of work on it and through quite a bit of engineers at it… but as is the nature of the horrible company that is micron… we see them routinely get greedy. Intel quickly cancelled their deal with micron after it was developed… LOL good move… anyways as a non-volatile memory, 3DXPoint has a number of features that distinguish it from other currently available RAM and NVRAM. Although the first generations of 3D XPoint were not especially large or fast, as of 2019 3D XPoint is used to create some of the fastest SSDs available, with small-write latency (the hardest type of task for most SSDs, sometimes described as “worst case” or “murderously” hard) being an order of magnitude faster than any preceding enterprise SSD. As the memory is inherently fast, and byte-addressable, techniques such as read-modify-write and caching used to enhance traditional SSDs are not needed to obtain high performance. In addition, chipsets such as Cascade Lake are designed with inbuilt support for 3D XPoint, that allow it to be used as a caching or acceleration disk, and it is also fast enough to be used as non-voltatile RAM (NVRAM) in a DIMM package.

IT IS NOT GOOD as RAM and it will definitely slow down operations significantly. It was never designed for this purpose and can present security risks… So I would not use it as ram unless your data center level and use encrypted ram. RAM is primarily developed for high throughput and bandwidth… 3D Xpoint was developed and is a rather great product for Low Latency… theres differences here which make them not cross well

You will see its use primarily in data centers especially for analytics as it provides a boost. Its not meant for a swap file nor will it ever be setup in that way… See Optimizing In-Memory Databases for Advanced Analytics in Multi-Cloud Environments

Intel Optane is architecture independent so it would be compatible with AMD epyc for example

Microns QuantX is very much locked down… strictly allowed only with micron products… and well not very prevalent… Again greed always gets the best of this company

P.S they treat their engineers like absolute shit so if your reading this and thinking of working there dont… cuz it gets worse if your a non engineer… youll just get laid off in 6 months … KEK

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