profile

#!/usr/bin/env python3

# interactive log-log profiling visualizer with scales I personally find useful for microprocessor-scale optimizations

# usage: ./profile <depth> <filename>
#
# "depth" is basically the height of the graph
# it controlls how many samples are stored at any given time

# legend for reading the output
#
# - ---------- ---------- -
# ^     ^          ^      ^
# |     |          |      '- more than a second
# |     |          |
# |     |          '- milliseconds
# |     |
# |     '- microseconds
# |
# '- less than a microsecond


import sys

from subprocess import PIPE, Popen


def render(depth, buckets):
    document = ''
    for y in reversed(range(0, depth, 2)):
        for x in range(25):
            # horizontal gaps
            if 0 != (x + 10) % 11:
                i = x - (x + 10) // 11
                document += [' ', '.', ':'][max(0, min(2, buckets[i] - y))]
            else:
                document += ' '
        document += '\n'
    document += '- ---------- ---------- -'
    return document


def main(depth, filename):
    height = depth // 2 + 1
    buflen = 2 ** depth

    proc = Popen(
        ['tail', '-fn', str(buflen), '--', filename],
        stdout=PIPE, text=True,
    )
    buffer = []

    try:
        # overprint
        print('\n' * height)
        for line in proc.stdout:
            value = int(line).bit_length()
            buffer = buffer[1-buflen:] + [value]
            buckets = [0] * 22
            for x in buffer:
                buckets[min(21, x)] += 1
            buckets = [int.bit_length(x) for x in buckets]
            # overprint
            print(f'\x1b[{1 + height}A')
            print(render(depth, buckets))
    except KeyboardInterrupt:
        print('\r', end='')
    finally:
        proc.kill()
        proc.wait()


(_, depth, filename) = sys.argv
main(int(depth), filename)