{"action":"created","issue":{"url":"https://api.github.com/repos/webpack/css-loader/issues/124","repository_url":"https://api.github.com/repos/webpack/css-loader","labels_url":"https://api.github.com/repos/webpack/css-loader/issues/124/labels{/name}","comments_url":"https://api.github.com/repos/webpack/css-loader/issues/124/comments","events_url":"https://api.github.com/repos/webpack/css-loader/issues/124/events","html_url":"https://github.com/webpack/css-loader/issues/124","id":100770333,"number":124,"title":"0.15.0+ makes Webpack load slowly","user":{"login":"ljconde","id":10686559,"avatar_url":"https://avatars.githubusercontent.com/u/10686559?v=3","gravatar_id":"","url":"https://api.github.com/users/ljconde","html_url":"https://github.com/ljconde","followers_url":"https://api.github.com/users/ljconde/followers","following_url":"https://api.github.com/users/ljconde/following{/other_user}","gists_url":"https://api.github.com/users/ljconde/gists{/gist_id}","starred_url":"https://api.github.com/users/ljconde/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ljconde/subscriptions","organizations_url":"https://api.github.com/users/ljconde/orgs","repos_url":"https://api.github.com/users/ljconde/repos","events_url":"https://api.github.com/users/ljconde/events{/privacy}","received_events_url":"https://api.github.com/users/ljconde/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":30,"created_at":"2015-08-13T13:33:50Z","updated_at":"2016-04-22T07:21:21Z","closed_at":null,"body":"Ever since the 0.15.0 update, I've had to revert back to 0.14.5, because Webpack loads very slowly (12 secs vs almost 60 secs). Is there a breaking change I should be aware of? Maybe something regarding PostCSS?"},"comment":{"url":"https://api.github.com/repos/webpack/css-loader/issues/comments/213300109","html_url":"https://github.com/webpack/css-loader/issues/124#issuecomment-213300109","issue_url":"https://api.github.com/repos/webpack/css-loader/issues/124","id":213300109,"user":{"login":"psimyn","id":1731922,"avatar_url":"https://avatars.githubusercontent.com/u/1731922?v=3","gravatar_id":"","url":"https://api.github.com/users/psimyn","html_url":"https://github.com/psimyn","followers_url":"https://api.github.com/users/psimyn/followers","following_url":"https://api.github.com/users/psimyn/following{/other_user}","gists_url":"https://api.github.com/users/psimyn/gists{/gist_id}","starred_url":"https://api.github.com/users/psimyn/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/psimyn/subscriptions","organizations_url":"https://api.github.com/users/psimyn/orgs","repos_url":"https://api.github.com/users/psimyn/repos","events_url":"https://api.github.com/users/psimyn/events{/privacy}","received_events_url":"https://api.github.com/users/psimyn/received_events","type":"User","site_admin":false},"created_at":"2016-04-22T07:21:21Z","updated_at":"2016-04-22T07:21:21Z","body":"i noticed that even though 'postcss-modules' stuff was taking the longest, it was still in the order of milliseconds whereas the actual wait time was seconds. ran a trace with `node --prof ./node_modules/.bin/webpack`, then loaded it in chrome's about://tracing view\r\n\r\nIt showed a huge amount of time (~75%) was being spent in url-resolver's Rework calls, so probably not css-loader-related.\r\n\r\nremoving sourceMap from sass-loader options has given ~400% speedup (from sometimes minutes down to ~30 seconds). Subsequent profiles have been more balanced (mix of all loaders).\r\n\r\nCan people try disabling sourcemaps and see if that improves. I will try to look into why it's having such an effect, or if there are some other optimisations for for loader"}}