# Create read+events (10 sockts):
#   Without the patch: Best of 25 runs (100000 loops, 10 FDs): 1294 ns per call to epoll.poll()
#   With the patch: Best of 50 runs (100000 loops, 10 FDs): 1221 ns (-6%) per call to epoll.poll()
#
# Create read+events (8000 sockts):
#   Without the patch: Best of 25 runs (10 loops, 16000 FDs): 4.6 ms per call to epoll.poll()
#   With the patch: Best of 25 runs (10 loops, 16000 FDs): 4.6 ms (same) per call to epoll.poll()
#
# Don't create events (10 sockets):
#   Without the patch: Best of 50 runs (100000 loops, 10 FDs): 367 ns per call to epoll.poll()
#   With the patch: Best of 50 runs (100000 loops, 10 FDs): 343 ns (-7%) per call to epoll.poll()
#
# Don't create events (1000 sockets):
#   Without the patch: Best of 50 runs (100000 loops, 1000 FDs): 420 ns per call to epoll.poll()
#   With the patch: Best of 50 runs (100000 loops, 1000 FDs): 326 ns (-22%) per call to epoll.poll()
#
# Don't create events (16000 sockets):
#   Without the patch: Best of 50 runs (100000 loops, 16000 FDs): 422 ns per call to epoll.poll()
#   With the patch: Best of 50 runs (100000 loops, 16000 FDs): 338 ns (-20%) per call to epoll.poll()

import os
import select
import time
import socket

#NPAIRS = 5 # number of socketpairs
NPAIRS = 500 # number of socketpairs
#NPAIRS = 8000 # number of socketpairs
NRUN = 25
READ = False # create read events?
WRITE = False # create write events?
if (READ or WRITE) and NPAIRS > 1000:
    NLOOP = 10
else:
    NLOOP = 10**5

socketpairs = []
while len(socketpairs) < NPAIRS:
    try:
        r, w = socket.socketpair()
    except OSError:
        break
    socketpairs.append((r, w))
nfds = len(socketpairs) * 2

print("Benchmark with %s FDs (%s socket pairs)"
      % (nfds, len(socketpairs)))
if READ:
    print("Create read events")
if WRITE:
    print("Create write events")
if not(READ or WRITE):
    print("Don't create events (epoll.poll() always return an empty list)")

poller = select.epoll()
for r, w in socketpairs:
    poller.register(r.fileno(), select.EPOLLIN)
    if WRITE:
        poller.register(w.fileno(), select.EPOLLOUT)

max_events = nfds
times = []
for run in range(NRUN):
    # create socketpairs/2 events
    if READ:
        for r, w in socketpairs:
            w.send(b'hello')

    start = time.perf_counter()
    for loop in range(NLOOP):
        poller.poll(0, max_events)
    dt = time.perf_counter() - start

    if READ:
        for r, w in socketpairs:
            data = r.recv(1024)
            assert data == b'hello'

    times.append(dt / NLOOP)

poller.close()

dt = min(times)
if dt >= 2e-3:
    dt = "%.1f ms" % (dt * 1e3)
elif dt >= 2e-6:
    dt = "%.1f us" % (dt * 1e6)
else:
    dt = "%.0f ns" % (dt * 1e9)
print("Best of %s runs (%s loops, %s FDs): %s per call to epoll.poll()"
      % (NRUN, NLOOP, nfds, dt))

for r, w in socketpairs:
    r.close()
    w.close()