plot.py

# Script to generate performance graph for utf8.Valid.
# Takes output of go test -bench as stdin.
#
#   make && go test ./utf8 -run=None -bench=BenchmarkValid|tee out.txt
#   python plot.py < out.txt
#   open data.png


import fileinput
import re
import tempfile
import os

data = {}


for line in fileinput.input():
    if "BenchmarkValid/small" not in line:
        continue
    x = re.search(r'BenchmarkValid/small([0-9]+)/([a-zA-Z]+)-[0-9]+.+?([0-9.]+) ns/op', line)
    if x == None:
        continue
    size, name, time = x.groups()
    size = int(size)
    time = float(time)
    name = name.lower()

    if name not in data:
        data[name] = []
    data[name].append((size, time))


dataFile = 'plot.dat'
titles = []

with open(dataFile, 'w+') as f:
    first = True
    for name, points in data.items():
        titles.append(name)
        if not first:
            print("\n", file=f)
        points = sorted(points)
        for x, y in points:
            print(" {}  {}".format(x, y), file=f)
        first = False

scriptFile = 'plot.p'
output = 'data.png'

with open(scriptFile, 'w+') as f:
    print(f"""
set terminal svg enhanced mouse size 1024,758
set terminal pngcairo size 1024,758

set output '{output}'

set ylabel 'ns/op'
set xlabel 'bytes'

set key inside bottom right
""", file=f)

    first = True
    idx = 0
    for title in titles:
        if not first:
            print(", \\", file=f)
        fileName = dataFile if first else ''
        command = 'plot' if first else '    '
        print(f"{command} '{fileName}' index {idx} with linespoints linestyle {idx+1} title \"{title}\"".format(), file=f, end='')
        first = False
        idx += 1
    print("", file=f)

os.system(f"gnuplot {scriptFile}")

print(f"Result written to {output}")