is there a way to add latency to PMEM emulator?

[dong]

Hi all,

We are building a db prototype on pmem devices. We do not have the phyiscal device yet, so did all the benchmarks on the emulator (by editing Grub to specify part of the DRAM as PMEM).  This does not add latency.  I am wondering is there a way to add latency? 

If not, are there places where we can try some benchmarks on real PMEM devices? Or maybe we can use Quartz?

Thanks and best,

- Dong

[Andy Rudoff]

Hi Dong,

I don't have a great answer to this.  When emulating pmem using DRAM, the only practical way I've found to add latency is to bind your program to one socket and use the local DRAM as DRAM, and the remote DRAM as pmem.  This isn't the correct latency for the actual product, but at least it adds the remote hop latency so you can see the effect of longer latencies in your benchmarks.

But like I said that's not a great answer and there's really no substitute for benchmarking on the actual hardware.

-andy

[dong]

Hi Andy,

Thanks so much for the quick reply. 

May I ask whether there would be some testing machines that people in academic setting can temporarily use or test?  I am asking this because I used to apply a testing machine from Intel for testing optane DC p4800x.

thanks and best,

- Dong