I do a very simple arpeggio warmup.
Start on F# on E string, and play maj arpeggios up the strings.
When you get to B on the G string, move your pinky up one fret and do arpeggios backwards back down, then move your index up one fret on G, etc etc. up the neck.
Start very slow, play perfectly, then increase speed with a tempo.
Repeat with minor triads (starting on F vs. F#)
Good warmup.