gnuplot read unix timestamp

Question

I have a file with data in this format:

1351649601.045 421 2945
1351649601.684 1036 28591
1351649603.310 128 1620
1351649603.413 93 0
1351649603.375 132 1762
1351649603.318 218 1761
1351649603.434 412 176
1351649603.441 520 5780
1351649603.480 565 11070
1351649603.556 644 11535


gnuplot> set term png
Terminal type set to 'png'
gnuplot> set output "output.png"
gnuplot> plot "data.txt" using 1:2 with lines

however, the date is not read properly by gnuplot. Do you have any ideas?

solved:

set term png xffffff
set output "output.png"
set size 17,17
set title "HTTP payload size and response time"
set style data fsteps
set xlabel "Date"
set timefmt "%s"
set format x "%m/%d/%Y %H:%M:%S"
set xdata time
set ylabel "Payload/Response time"
set grid
set key left
plot 'response' usi 1:2 with linespoints

Answer 1

Sorry, can't seem to delete. Was going to suggest:

set xdata time
set timefmt "%s"
set format x "%m/%d/%Y %H:%M:%S"
plot "file.txt" using 1:2 with linespoints

But it truncates the fraction and drops points from the line.