{"action":"created","issue":{"url":"https://api.github.com/repos/docker/docker/issues/13985","labels_url":"https://api.github.com/repos/docker/docker/issues/13985/labels{/name}","comments_url":"https://api.github.com/repos/docker/docker/issues/13985/comments","events_url":"https://api.github.com/repos/docker/docker/issues/13985/events","html_url":"https://github.com/docker/docker/issues/13985","id":88972536,"number":13985,"title":"I/O performance issues with extra process","user":{"login":"robertoaloi","id":91769,"avatar_url":"https://avatars.githubusercontent.com/u/91769?v=3","gravatar_id":"","url":"https://api.github.com/users/robertoaloi","html_url":"https://github.com/robertoaloi","followers_url":"https://api.github.com/users/robertoaloi/followers","following_url":"https://api.github.com/users/robertoaloi/following{/other_user}","gists_url":"https://api.github.com/users/robertoaloi/gists{/gist_id}","starred_url":"https://api.github.com/users/robertoaloi/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/robertoaloi/subscriptions","organizations_url":"https://api.github.com/users/robertoaloi/orgs","repos_url":"https://api.github.com/users/robertoaloi/repos","events_url":"https://api.github.com/users/robertoaloi/events{/privacy}","received_events_url":"https://api.github.com/users/robertoaloi/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-06-17T09:53:46Z","updated_at":"2015-06-18T15:25:12Z","closed_at":null,"body":"Given the following minimal Dockerfile, which installs the _erlang_ package on a centos6:\r\n\r\n    FROM centos:centos6\r\n    RUN yum update -y && \\\r\n        yum install -y https://www.rabbitmq.com/releases/erlang/erlang-17.4-1.el6.x8\r\n\r\nThere's a substantial difference in performance if I execute a \"I/O heavy\" operation from the process specified as the Docker \"command\" or via an extra process.\r\n\r\n    (Docker 1.6.2)\r\n    sudo docker build -t test .\r\n \r\n    # The following is fast ~1s\r\n    sudo docker run -it test erl\r\n    {T, V} = timer:tc(os, cmd, [\"grep -ir test /usr\"]), T.\r\n \r\n    # The following is slow ~10s\r\n    sudo docker run -it test bash\r\n    erl\r\n    {T, V} = timer:tc(os, cmd, [\"grep -ir test /usr\"]), T.\r\n \r\nIs this expected? I'm running Docker 1.6.2.\r\n\r\nTo make things more interesting, \"sh\" doesn't seem to suffer the same issue:\r\n\r\n    # The following is fast ~1s\r\n    sudo docker run -it test sh\r\n    erl\r\n    {T, V} = timer:tc(os, cmd, [\"grep -ir test /usr\"]), T.\r\n\r\nReference: https://gist.github.com/robertoaloi/9bb95c620803baef2d7f"},"comment":{"url":"https://api.github.com/repos/docker/docker/issues/comments/113191296","html_url":"https://github.com/docker/docker/issues/13985#issuecomment-113191296","issue_url":"https://api.github.com/repos/docker/docker/issues/13985","id":113191296,"user":{"login":"unclejack","id":1409668,"avatar_url":"https://avatars.githubusercontent.com/u/1409668?v=3","gravatar_id":"","url":"https://api.github.com/users/unclejack","html_url":"https://github.com/unclejack","followers_url":"https://api.github.com/users/unclejack/followers","following_url":"https://api.github.com/users/unclejack/following{/other_user}","gists_url":"https://api.github.com/users/unclejack/gists{/gist_id}","starred_url":"https://api.github.com/users/unclejack/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/unclejack/subscriptions","organizations_url":"https://api.github.com/users/unclejack/orgs","repos_url":"https://api.github.com/users/unclejack/repos","events_url":"https://api.github.com/users/unclejack/events{/privacy}","received_events_url":"https://api.github.com/users/unclejack/received_events","type":"User","site_admin":false},"created_at":"2015-06-18T15:25:12Z","updated_at":"2015-06-18T15:25:12Z","body":"@robertoaloi Can you please get rid of erlang from the example and try to reproduce without erlang? That would let us know if this is a problem caused by erlang on that system or if it's something else."}}