Data transfer rate with different interfaces

[krmld]

[aolofsson]

[krmld]

[sebraa]

Using the current images, I did a few measurements.

I run a direct connection between an Intel GBit Ethernet and the Parallella, and ran the following commands:
on the laptop: "dd if=/dev/zero bs=1M | pv | nc parallella 12345"
on the parallella: "nc -lp 12345 | pv >/dev/null"

I got about 40 MiB/s, with the Parallella being 75% busy (1 core netcat, 1/2 core pv), using the newest image on a stock configuration.

[aolofsson]

[sebraa]

Using iperf, I get about 520 MBit/s (laptop as server), or about 580 MBit/s (Parallella as server).
When testing both directions at once (-d parameter), I get about (35 / 187) MBit/s (laptop as server; but differing widely), or about (380 / 120) MBit/s (Parallella as server).

Again, this is on a stock configuration using the 3.14.12-parallella-xilinx-g40a90c3 kernel.

[ajtravis]

[tnt]

If you want to improve performance a bit :
- Use larger MTU on network
- Use more aggressive DDR timings (the default ones are _very_ conservative, way under what the components are spec'd for).
- Use a memcpy library with optimized NEON code

[sebraa]

I only wanted to see whether the extremely low numbers reported in the first post are realistic. I don't care too much about getting higher numbers. My workloads are limited by other means, not by the network interface, and the only Epiphany cluster available to us uses a 100 MBit/s switch (don't ask me, I didn't build it...).

The dd/netcat combination was chosen since it is not a benchmark, but a somewhat more realistic workload (that is, both cores working together to produce data elements).