Byte addressable with PMDK using Intel Optane Memory

[Pedro Ramalhete]

Hello,

In the pmem.io page it says that PMDK works with Intel's 3D XPoint:
http://pmem.io/documents/
Does this mean that it also works with Intel Optane Memory product, even though it's not directly byte-addressable?
If yes, then any pointers to the magical incantations required to get that working with PMDK would be appreciated.

Thanks,
Pedro

[Andy Rudoff]

Hi Pedro,

PMDK is optimized for byte-addressable memory, so it heavily leverages things like the ability to flush individual cache lines to persistence.  It will technically "work" with any file system on any type of media (hard drive, NAND SSDs, Optane SSDs) but the performance won't be that useful because each time one of the PMDK libraries flushes a 64-byte cache line, the only way for storage products to flush that data is to write an entire block.  We make it work correctly in the library so that people can develop and debug their code using any storage device -- just create a file and the library will memory map it and use it.  But it will be "paging" blocks to and from the storage device, as I explained, so the performance won't be interesting until you use PMDK on an actual byte-addressable persistent memory device.  The currently shipping NVDIMM-N products will perform well, as will the upcoming 3D XPoint DIMM from Intel.

Hope that clarifies it.

-andy