Hi Glen, I assume you are running your fabric > 125MHz? What is the data rate you are trying to sustain?
HK On Mon, Jul 27, 2015 at 10:06 PM, G Jones <[email protected]> wrote: > Hi, > I'm experimenting with the one_gbe block on ROACH2. So far data > transmission looks flawless, I can capture all the bytes I send. However, > receiving data from a computer seems to result in missing data. > My design is very simple, I have rx_ack tied high, and then counters on > rx_val and the rising edge of rx_eof and also on rx_overrun and rx_badframe. > > If I just send a single packet, all looks good, the rx_val counter shows > the number of bytes I sent, and rx_eof shows one packet received. But when > I try to send a sequence of packets, I end up with the rx_val counter > showing fewer bytes than I sent, by about ~ 0.5-5% depending on the exact > combination of parameters I use in sending packets. Sometimes all the ~1024 > packets arrive, as indicated by the rx_eof counter, but other times it > seems 1-3 are missing. > > I see consistent results whether the packet payload is 1024 bytes, 4096 > bytes, or 8192 bytes. > > I never see any counts on the rx_overrun or rx_badframe line. > > I am using sendall to send the packets from the host computer, and it > reports that all bytes are being sent, so I assume it's not dropping them > on the way outbound (plus it seems like it would be weird for the host > computer to send partial packets). > > I've tried this test with two different network adapters (both directly > connected to the ROACH2 fabric ethernet port, and with various lengths of > CAT 6 ethernet cables. > > Has anyone used the one_gbe block in this way? Am I missing something? > > Thanks, > Glenn > -- Kind regards, Henno Kriel Manager: Hardware Engineering SKA South Africa (p) +27 (0)21 506 7374 (direct) (m) +27 (0)84 504 5050 web: www.ska.ac.za
