Performance Co-Pilot and grafana

I am new to grafana and I have configured PCP with pmwebd (package pcp-webapi), this also gives a graphite plot you can use as datasource URL into grafana, and that prints the metric I have, at this point all is fine, the problem i have is with the legend, the grafana dashboard has a very long legend name (it prints the name of the process in my case and that is a very long name) the thing that I need is to shorten the legend to only show one field of all this long legend, do you know how i can do that?

The software i have installed: