René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"stdin.drain is very slow on some platforms","articleBody":"I'm on Python 3.5.2, with the following code:\n\n``` python\n#!/usr/bin/env python3\n\nimport asyncio\nimport time\nimport logging\n\nlogging.basicConfig(level='DEBUG')\n\nasync def drain_time(length):\n    proc = await asyncio.create_subprocess_exec('/bin/cat',\n        stdin=asyncio.subprocess.PIPE,\n        stdout=asyncio.subprocess.DEVNULL,\n        stderr=asyncio.subprocess.DEVNULL,\n    )\n\n    data = b'0' * length\n    proc.stdin.write(data)\n    t0 = time.time()\n    await proc.stdin.drain()\n    r = time.time() - t0\n    proc.stdin.close()\n    await proc.wait()\n    return r\n\nasync def main():\n    for i in range(5, 17):\n        for j in range(1, 2):\n            size = j * 10**i\n            print('{:.0e}'.format(size), await drain_time(size))\n\nasyncio.get_event_loop().run_until_complete(main())\n```\n\non an Ubuntu server (this seems ok)\n\n```\nDEBUG:asyncio:Using selector: EpollSelector\n1e+05 7.3909759521484375e-06\n2e+05 6.4373016357421875e-06\n3e+05 0.000118255615234375\n1e+06 0.0002932548522949219\n2e+06 0.0005526542663574219\n3e+06 0.0019674301147460938\n1e+07 0.023283720016479492\n2e+07 0.004916667938232422\n3e+07 0.16347408294677734\n1e+08 0.024138450622558594\n2e+08 0.04891180992126465\n3e+08 0.07430100440979004\n```\n\non an Archlinux: (more or less ok)\n\n```\nDEBUG:asyncio:Using selector: EpollSelector\n1e+05 5.245208740234375e-06\n2e+05 4.291534423828125e-06\n3e+05 8.797645568847656e-05\n1e+06 0.0005102157592773438\n2e+06 0.0015668869018554688\n3e+06 0.0022423267364501953\n1e+07 0.01090097427368164\n2e+07 0.1207735538482666\n3e+07 0.2826368808746338\n1e+08 0.8428807258605957\n2e+08 0.029124975204467773\n3e+08 3.3120124340057373\n1e+09 2.904399871826172\n2e+09 13.772144079208374\n3e+09 16.17424488067627\n```\n\non osx: (not ok)\n\n```\nDEBUG:asyncio:Using selector: KqueueSelector\n1e+05 0.0005750656127929688\n2e+05 0.0010769367218017578\n3e+05 0.005205869674682617\n1e+06 0.007627964019775391\n2e+06 0.022066831588745117\n3e+06 0.05894899368286133\n1e+07 1.633073091506958\n2e+07 6.287441968917847\n3e+07 15.285433053970337\n1e+08 178.50560998916626\n```\n\nAny idea what could be causing this?\n","author":{"url":"https://github.com/arthurdarcet","@type":"Person","name":"arthurdarcet"},"datePublished":"2016-07-22T09:06:16.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/384/asyncio/issues/384"}