set terminal png
set output ofilename 
set timefmt "%d:%H:%M:%S"
set format x "%M:%S"
set xdata time
set xlabel "Time (M:S)"
set ylabel "qps"
set style data line
plot ifilename every ::2 using 1:6 t 'qps', '' every ::2 using 1:7 t 'cps'
