ROACH2's PHY is different. It's now Marvel (as opposed to a National Semi on
ROACH1). It works reliably at 1Gbps.
I bank on 10Mb/s on ROACH1, which is achievable using the normal katcp and
tcpborphserver2 without any trickery. You can get better if you write your own
PPC code.
ROACH2 should
Hi, Jason,
Why only a factor of 2 faster instead of a factor of 10? What is the limiting
factor other than ethernet speed?
10 Mbps throughput over a 100 Mbps link (10% efficiency) seems not so great but
understandable/acceptable.
20 Mbps throughput over a 1,000 Mbps link (2% efficiency)
hi dave,
the PPC ethernet bottleneck is in the PPC code needed
to read data from the FPGA, format the data,
and write it to the ethernet port
.
if you spend work at optimizing your code,
you can get a higher data rate.
dan
On Mon, Apr 29, 2013 at 8:35 AM, David MacMahon
Hi all.
Can someone tell me if the ethernet port on the newer ROACH boards is
reliable at 1 gb/s?
Also, what is the maximum data rate expected through that interface?
Thanks!
John
hi john,
i think all roach1's PPC ethernet ports need to be used at 100Mb/sec port
speed,
independent of when the boards were made, and not at 1Gbit/sec.
it's tricky to write PPC software that gets more than 20Mbit/sec
out of the port, but i'm not sure about this 20Mbit/sec number.
best wishes,
hi john,
i think all roach1's PPC ethernet ports need to be used at 100Mb/sec port
speed,
independent of when the boards were made, and not at 1Gbit/sec.
Thanks, Dan. I thought that a PHY chip had been changed, but I couldn't
remember. Now I seem to recall that the Phy is just Not Good.
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