How to calculate memory bandwidth using EMC_FREQ x%@y from Tegrastate log for Jetson Nano.

Hi,

We have to calculate memory bandwidth using EMC_FREQ x%@y from Tegrastate log for Jetson Nano.

As per the below link memory bandwidth should be calculated using this formula.

y * x% * <magic #>.

https://devtalk.nvidia.com/default/topic/1066512/jetson-agx-xavier/measuring-ddr-bandwidth-/

So, what can be this magic number for the Jetson Nano.

It would be grateful, if anyone can say same for TX2 board also.

Hi mamtesh.k,

Please refer to tegrastats Utility section at L4T development guide to get more understanding:
https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2FAppendixTegraStats.html%23

Hi Kayccc,

There is nothing in tegrastats Utility section to calculate the Memory Bandwidth(in GB/sec).

There is only description of x and y for EMC_FREQ x%@y. We want to know Memory Bandwidth(in GB/sec) using these value.

This didn’t answer my question.

hello mamtesh.k,

may I know what’s your purpose to calculate the memory bandwidth?
here’s CUDA samples that query for memory bandwidth, you may check Topic 1024058 for reference,
thanks

Hi JerryChang,

Thanks for your quick reply, We do some experiment to calculate the Memory bandwidth in some interval when we do any execution.

But I believe that “magic #” is nothing but memory width. And we can know memory width using device queries “https://devtalk.nvidia.com/default/topic/1024058/”.

Correct me If am I wrong.

Thanks!