15 lines (13 with data), 334 Bytes

set terminal postscript landscape enhanced color
set output 'plotL.ps'
set autoscale
set title "Number of cores vs time"
set xlabel "time (secs)"
set ylabel "cores"
plot 'hist' using 1:2
set title "Size of job list L vs time"
set ylabel "L"
plot 'hist' using 1:3
set title "Requests vs time"
set ylabel "cores"
plot 'hist' using 1:4