Hi Homin,

Could this be due to a rouge ARP process? We have seen failure modes where
the ARP configuration fills itself with FF:FF:FF:FF and starts broadcasting
UDP traffic. We hard-code the ARP table to stop this.

I also recall reading something similar to do with anti-flood contorl on
some switches, might be worth double-checking if there's an unusual
'feature' that turns on after a metric is reached.

Good luck debugging!

Regards,
Danny


On 13 March 2018 at 4:01:13 pm, Homin Jiang (ho...@asiaa.sinica.edu.tw)
wrote:

Hi Dave:

Thanks of prompt response and suggestion.
The X engine is running the same clock as the F engine, 2.24GHz/8 = 280MHz.
Perhaps I should increase the clock in X engine ?
Yes, there is Tx overflow flag in the model, it will be the first thing for
me to check.

best
homin



On Tue, Mar 13, 2018 at 12:42 PM, David MacMahon <dav...@berkeley.edu>
wrote:

> Hi, Homin,
>
> The first thing to do is figure out where packet loss is actually
> happening.  The fact that you have to reset the 10G yellow blocks to get
> things going again suggests that the X engines are not keeping up with the
> data rate (since the F engines will happily churn out 8.96 Gbps data
> regardless of the receivers' states and the X engines will happily churn
> out data regardless of the PC's state, it seems that the only way for the
> 10 GbE blocks to get confused is if the X engines are not keep up with the
> incoming data rate).  I assume the F engine ROACH2s are being clocked via
> their ADCs.  How are the X engine ROACH2s being clocked?
>
> Assuming the F-to-X packets are going through a switch, you could query
> the switch to see what it thinks the incoming and outgoing data rates are
> on the various ports involved.
>
> Does your design have any way of capturing the overflow flags of the 10
> GbE cores?
>
> Dave
>
> On Mar 12, 2018, at 19:39, Homin Jiang <ho...@asiaa.sinica.edu.tw> wrote:
>
> Dear Casperite:
>
> We have been deployed a 7(actually 8) antenna packetized correlator on
> Mauna Loa Hawaii. Running at 2.24GHz clock, that means 8.96 G bits per
> second for each 10G ethernet. The packet size is 2K. There are 8 sets of
> ROACH2 as F engines, the other 8 sets of ROACH2 as X engines. Data packets
> from F to X looks fine, the problem of lost packets is the integration data
> from X engine to the computer. The 10G yellow blocks in X engines handle
> the incoming data packets from F engine at the data rate of 8.96 Gbps, and
> output the integration data to PC, the outgoing data rate depends on the
> integration time, usually it is longer than 0.5 second. The syndrome is
> that packets lost happened by specific X engines after 10,20 minutes or
> couple of hours. Once it happened, we reset all the 10G yellow blocks in F
> and X, then the system revived.
>
> I have no idea about the 10G ethernet yellow block. Any comments of
> suggestions are highly welcome.
>
> best
> homin jiang
>
>
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