Intel's Memory Latency Checker (MLC) is showing a max read bandwidth of ~1.9TB/sec which is impossible since the theoretical max bandwidth for 12 channels is ~240 GB/sec

[KMani8]

System:

2x Intel Xeon CPU each with 6x memory channels.

Each channel has 1x 128GB Optane DIMM and 1x 32GB DRAM

Total: 12x Optane DIMM and 12x DRAM DIMMs.

I have 6 DIMMS (1 region) mapped to 1 fsdax namespace and I mounted this namespace to /mnt/pmem0/

Screenshot:

Did I set something up wrong? or is this a bug?

[Emeth_O_Intel · Accepted solution]

Hi,

Thank you for contacting Intel® Optane™ DC Persistent Memory Community Support. 

I was reviewing the information you have provided and I would like to ask you and provide you some very important details about it:

1. Which Memory Operational Mode did you configure on your system?

Also, I can see that you mention: (You have 6 DIMMS (1 region) mapped to 1 fsdax namespace and you mounted this namespace to /mnt/pmem0/)

However, The default behavior of Intel MLC is to test only DRAM or Intel Optane DC persistent memory modules when configured in Memory Mode. To test Intel Optane DC persistent memory modules in App Direct Mode using Intel MLC, the namespaces must be created using devdax mode.

Intel MLC testing can be configured to use the /dev/daxN.M device(s). The Intel MLC documentation included in the download bundle has several examples for using devdax devices. To test fsdax, sector, or raw, a higher-level benchmark utility such as Flexible I/O Tester (FIO) should be used.

For the Flexible IO Tester (FIO); please check the following link under the section name "Flexible IO Tester (FIO)":

https://software.intel.com/en-us/articles/configure-manage-and-profile-intel-optane-dc-persistent-memory-modules

Please let me know if this information helps you to gather the properly results.

Have a wonderful day.

Emeth O.

Intel Customer Support Technician.

Under Contract to Intel Corporation.

[Emeth_O_Intel]

Hi,

I would like to know if the information provided helps you to clarify your questions.

If you have more questions do not hesitate and let me know and I will be more than happy to assist you.

Have a wonderful day.

Regards.

Emeth O.

Intel Customer Support Technician

A Contingent Worker at Intel

[Emeth_O_Intel]

Hi,

Due to the fact I have not seen any activity recently.

I will proceed and close this thread. If you have more questions do not hesitate and contact us back and we will be more than happy to assist you.

Regards,

Emeth O.

Intel Customer Support Technician

A Contingent Worker at Intel