Hi Dima, > Hi. Notes inline.
Thanks for your quick reply! >> I cannot get dynamic plots to work on my system. > > OK. I suspect this is something on your end, but let's run some > experiments. I am 100% sure it is something on my end. The question is if it is my fault or reproducible on other machines as well ;) >> while true; do sleep 1; cat /proc/net/dev; done | >> gawk '/enp6s0/ {if(b) {print $2-b; fflush()} b=$2}' | >> feedgnuplot --lines --stream --xlen 10 --ylabel 'Bytes/sec' --xlabel seconds >> >> This opens up a gnuplot window but it is not updating every second as >> it should. The lower left corner seems to be showing a coordinate and >> this indeed updates every second, but the plot itself does not. From >> time to time the plot gets redrawn but then again stays fixed. > > I can think of several potential causes. First off, let's eliminate X > issues. Can you please add '--terminal "dumb 80 40"' to the feedgnuplot > command? If that works properly, you'll see an ascii plot printed onto > your console every second. Do you see that? Works like a charm. >> Doing more diagnosing, I used the --dump switch to see what is being fed into >> gnuplot and when I manually run gnuplot and paste the fragments into it, it >> works just fine. It seems to be related with the fact that gnuplot reads the >> input from the pipe. > > Right. The second theory is that it's something related to buffering. > That command should handle it, but let's see. Try this: > > 1. apt install mawk > > 2. while true; do sleep 1; cat /proc/net/dev; done | > mawk -Winteractive '/enp6s0/ {if(b) {print $2-b} b=$2}' | > feedgnuplot --lines --stream --xlen 10 --ylabel 'Bytes/sec' --xlabel seconds > --terminal 'dumb 80 40' > > So use "mawk -Winteractive" instead of "gawk", and remove the fflush(). > Does that make any difference? Nope. Same behaviour. Position in lower left corner updates, graph does not. Only one update after approximately 8 seconds then again fixed. >> Maybe this is related to the gnuplot version in Bullseye? > > Maybe, but I doubt it. Please run the two experiments above, and we can > go from there. I should have mentioned I only recently switched from GNOME on Xorg to GNOME on Wayland. I hope it does not make a difference but I wanted to mention it. Any other ideas? Thanks in advance! Detlev -- Any fool can write code that a computer can understand. Good programmers write code that humans can understand. -- Martin Fowler