Current numbers on my workstation:

CPython 3.6.4

//gevent36/bin/python bench_spawn.py eventlet --ignore-import-errors
using eventlet from //python3.6/site-packages/eventlet/__init__.py
spawning: 11.93 microseconds per greenlet
sleep(0): 23.49 microseconds per greenlet

//gevent36/bin/python bench_spawn.py gevent --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 3.39 microseconds per greenlet
sleep(0): 17.59 microseconds per greenlet

//gevent36/bin/python bench_spawn.py geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 8.71 microseconds per greenlet
sleep(0): 16.99 microseconds per greenlet
 joining: 7.34 microseconds per greenlet

//gevent36/bin/python bench_spawn.py geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 2.09 microseconds per greenlet
sleep(0): 13.57 microseconds per greenlet

//gevent36/bin/python bench_spawn.py none --ignore-import-errors
    noop: 0.33 microseconds per greenlet

//gevent36/bin/python bench_spawn.py --with-kwargs eventlet --ignore-import-errors
using eventlet from //python3.6/site-packages/eventlet/__init__.py
spawning: 12.06 microseconds per greenlet
sleep(0): 24.25 microseconds per greenlet

//gevent36/bin/python bench_spawn.py --with-kwargs gevent --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 4.62 microseconds per greenlet
sleep(0): 22.18 microseconds per greenlet

//gevent36/bin/python bench_spawn.py --with-kwargs geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 10.25 microseconds per greenlet
sleep(0): 18.89 microseconds per greenlet
 joining: 7.14 microseconds per greenlet

//gevent36/bin/python bench_spawn.py --with-kwargs geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 3.27 microseconds per greenlet
sleep(0): 15.03 microseconds per greenlet

//gevent36/bin/python bench_spawn.py --with-kwargs none --ignore-import-errors
    noop: 0.50 microseconds per greenlet

CPython 2.7.14

//gevent27/bin/python bench_spawn.py eventlet --ignore-import-errors
using eventlet from //python2.7/site-packages/eventlet/__init__.pyc
spawning: 17.84 microseconds per greenlet
sleep(0): 31.42 microseconds per greenlet

//gevent27/bin/python bench_spawn.py gevent --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 4.95 microseconds per greenlet
sleep(0): 21.40 microseconds per greenlet

//gevent27/bin/python bench_spawn.py geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 12.44 microseconds per greenlet
sleep(0): 22.90 microseconds per greenlet
 joining: 10.68 microseconds per greenlet

//gevent27/bin/python bench_spawn.py geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 2.33 microseconds per greenlet
sleep(0): 15.11 microseconds per greenlet

//gevent27/bin/python bench_spawn.py none --ignore-import-errors
    noop: 0.58 microseconds per greenlet

//gevent27/bin/python bench_spawn.py --with-kwargs eventlet --ignore-import-errors
using eventlet from //python2.7/site-packages/eventlet/__init__.pyc
spawning: 19.38 microseconds per greenlet
sleep(0): 31.62 microseconds per greenlet

//gevent27/bin/python bench_spawn.py --with-kwargs gevent --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 6.59 microseconds per greenlet
sleep(0): 23.12 microseconds per greenlet

//gevent27/bin/python bench_spawn.py --with-kwargs geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 13.78 microseconds per greenlet
sleep(0): 21.65 microseconds per greenlet
 joining: 10.86 microseconds per greenlet

//gevent27/bin/python bench_spawn.py --with-kwargs geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 3.59 microseconds per greenlet
sleep(0): 16.14 microseconds per greenlet

//gevent27/bin/python bench_spawn.py --with-kwargs none --ignore-import-errors
    noop: 0.65 microseconds per greenlet

PyPy2 5.10.0

//geventpypy/bin/python bench_spawn.py eventlet --ignore-import-errors
using eventlet from //geventpypy/site-packages/eventlet/__init__.pyc
spawning: 29.91 microseconds per greenlet
sleep(0): 84.24 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py gevent --ignore-import-errors
using gevent from //src/gevent/__init__.py
spawning: 0.73 microseconds per greenlet
sleep(0): 33.02 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 2.49 microseconds per greenlet
sleep(0): 38.56 microseconds per greenlet
 joining: 13.08 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 0.52 microseconds per greenlet
sleep(0): 29.63 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py none --ignore-import-errors
    noop: 0.02 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py --with-kwargs eventlet --ignore-import-errors
using eventlet from //geventpypy/site-packages/eventlet/__init__.pyc
spawning: 30.36 microseconds per greenlet
sleep(0): 83.00 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py --with-kwargs gevent --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 1.56 microseconds per greenlet
sleep(0): 34.80 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py --with-kwargs geventpool --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 3.48 microseconds per greenlet
sleep(0): 39.43 microseconds per greenlet
 joining: 16.21 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py --with-kwargs geventraw --ignore-import-errors
using gevent from //src/gevent/__init__.pyc
spawning: 1.51 microseconds per greenlet
sleep(0): 52.19 microseconds per greenlet

//geventpypy/bin/python bench_spawn.py --with-kwargs none --ignore-import-errors
    noop: 0.13 microseconds per greenlet

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