From b3cab9ed884c794daa3287994ada2e52457b8320 Mon Sep 17 00:00:00 2001
From: Arthur Darcet <arthur+github@darcet.fr>
Date: Sat, 19 Oct 2019 12:41:14 +0200
Subject: [PATCH] benchmarking script to time the different asyncio write
 options (#2179)

---
 tools/bench-asyncio-write.py | 118 +++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 tools/bench-asyncio-write.py

diff --git a/tools/bench-asyncio-write.py b/tools/bench-asyncio-write.py
new file mode 100644
index 00000000000..35c65891847
--- /dev/null
+++ b/tools/bench-asyncio-write.py
@@ -0,0 +1,118 @@
+import asyncio
+import atexit
+import math
+import os
+import signal
+
+PORT = 8888
+
+server = os.fork()
+if server == 0:
+    loop = asyncio.get_event_loop()
+    coro = asyncio.start_server(lambda *_: None, port=PORT)
+    loop.run_until_complete(coro)
+    loop.run_forever()
+else:
+    atexit.register(os.kill, server, signal.SIGTERM)
+
+
+async def write_joined_bytearray(writer, chunks):
+    body = bytearray(chunks[0])
+    for c in chunks[1:]:
+        body += c
+    writer.write(body)
+
+async def write_joined_list(writer, chunks):
+    body = b''.join(chunks)
+    writer.write(body)
+
+async def write_separately(writer, chunks):
+    for c in chunks:
+        writer.write(c)
+
+
+def fm_size(s, _fms=('', 'K', 'M', 'G')):
+    i = 0
+    while s >= 1024:
+        s /= 1024
+        i += 1
+    return '{:.0f}{}B'.format(s, _fms[i])
+def fm_time(s, _fms=('', 'm', 'µ', 'n')):
+    if s == 0:
+        return '0'
+    i = 0
+    while s < 1:
+        s *= 1000
+        i += 1
+    return '{:.2f}{}s'.format(s, _fms[i])
+
+
+writes = [
+    ("b''.join", write_joined_list),
+    ('bytearray', write_joined_bytearray),
+    ('multiple writes', write_separately),
+]
+
+bodies = (
+    [],
+    [10 * 2 ** 0 ],
+    [10 * 2 ** 7],
+    [10 * 2 ** 17],
+    [10 * 2 ** 27],
+    [50 * 2 ** 27],
+    [ 1 * 2 ** 0  for _ in range(10)],
+    [ 1 * 2 ** 7  for _ in range(10)],
+    [ 1 * 2 ** 17 for _ in range(10)],
+    [ 1 * 2 ** 27 for _ in range(10)],
+    [10 * 2 ** 27 for _ in range(5)],
+)
+
+jobs = [(
+    # always start with a 256B headers chunk
+    '{} / {}'.format(fm_size(sum(j) if j else 0), len(j)),
+    [b'0' * s for s in [256] + list(j)],
+) for j in bodies]
+
+async def time(loop, fn, *args):
+    spent = []
+    while not spent or sum(spent) < .2:
+        s = loop.time()
+        await fn(*args)
+        e = loop.time()
+        spent.append(e - s)
+    mean = sum(spent) / len(spent)
+    sd = sum((x - mean) ** 2 for x in spent) / len(spent)
+    return len(spent), mean, math.sqrt(sd)
+
+async def main(loop):
+    _, writer = await asyncio.open_connection(port=PORT)
+    print('Loop:', loop)
+    print('Transport:', writer._transport)
+    res = [
+        ('size/chunks', 'Write option', 'Mean', 'Std dev', 'loops', 'Variation'),
+    ]
+    res.append([':---', ':---', '---:', '---:', '---:', '---:'])
+
+    async def bench(job_title, w, body, base=None):
+        it, mean, sd = await time(loop, w[1], writer, c)
+        res.append((
+            job_title,
+            w[0],
+            fm_time(mean),
+            fm_time(sd),
+            str(it),
+            '{:.2%}'.format(mean / base - 1) if base is not None else '',
+        ))
+        return mean
+
+    for t, c in jobs:
+        print('Doing', t)
+        base = await bench(t, writes[0], c)
+        for w in writes[1:]:
+            await bench('', w, c, base)
+    with open('bench.md', 'w') as f:
+        for l in res:
+            f.write('| {} |\n'.format(' | '.join(l)))
+
+loop = asyncio.get_event_loop()
+loop.run_until_complete(main(loop))