Friday, August 21, 2015

Intel ATOM D525 Network Performance

I recently had the occasion to use a small Intel Atom D525 based Linux server to do some file transfers from one machine to another. I noticed that the file transfers were not very snappy, so I started to look closer at the issue. The Microtik switch that I'm using has a nice usage meter on each interface and I noticed that a single rsyc over ssh was only giving me 100-150Mb/s performance. Realizing that this was compressed and using the somewhat whimpy Atom CPU, I backed off to a minimal compression algorithm and ended up getting a modest improvement (200Mb/s). So, running 4 parallel rsyncs seemed to be the trick, but I seem to cap out around 5-600Mb/s:

The CPU seemed to hover around 40-50%, which was odd, I would have expected to see a higher percentage if my performance was capped.

I later tried NFS to see if that did the trick, but it too capped around 5-600Mb/s. The particular distribution of Linux I was using was Zentyal 3.5, but I also tried on an Ubuntu 14.04 Atom D525 system as well with the same results.

Just to make sure it wasn't something to do with the server I initiated a transfer from my desktop PC running Windows 7. You can see the server doesn't have any issues keeping up. In a later blog post I'll go into the ethernet switch I'm using and how changing the default queueing method affects performance in a positive manner.

The end result is that I wasn't able to push the Intel Atom D525 board beyond 5-600Mb/s. It could be an ethernet driver issue since the CPU didn't seem to be loaded beyond 50%, but I figured it would be an interesting datapoint to share. If anyone sees differently, please message me with your results.