Gr::log :WARN: udp_source0 - Too much data; dropping packet

I am writing a code where data is psk modulated in a host and then the
modulated psk symbols are sent over udp to a remote host where a
demodulator is setting.
I am having troubles getting it to work.
I have the following warning message filling the console.

“gr::log :WARN: udp_source0 - Too much data; dropping packet.”

It looks there is a flow control problem. However, I tried to increase
the buffer size of the source udp but I still have the same problem.

The code is very simple. It is:
in host 1: signal source >> packet encoder >> DPSK modulator >> udp

in host 2: udp source >> DPSK demodulator >> packet decoder >> GUI time

Hi Anis,
this indicates that the flowgraph downstream from the UDP source is too
slow processing the samples.
Therefore you a) need to make sure that the flow graph is as fast as
possible[0], and/or
b) get a faster computer and/or
c) not directly feed the samples to the flow graph but buffer them to
e.g. a named pipe [1] and read that using a file source, offering you a
much larger buffer.


[0] I habitually say the following: Don’t ever use a throttle block,
unless you need to throttle the flow of samples, which is almost never
the case (unless you’re visualizing signals that you generate
[1] “man fifo”, “man mkfifo”