{"action":"created","issue":{"url":"https://api.github.com/repos/nodejs/node/issues/9634","repository_url":"https://api.github.com/repos/nodejs/node","labels_url":"https://api.github.com/repos/nodejs/node/issues/9634/labels{/name}","comments_url":"https://api.github.com/repos/nodejs/node/issues/9634/comments","events_url":"https://api.github.com/repos/nodejs/node/issues/9634/events","html_url":"https://github.com/nodejs/node/issues/9634","id":189643506,"number":9634,"title":"Performance regression of instanceof in v7 and master","user":{"login":"mcollina","id":52195,"avatar_url":"https://avatars.githubusercontent.com/u/52195?v=3","gravatar_id":"","url":"https://api.github.com/users/mcollina","html_url":"https://github.com/mcollina","followers_url":"https://api.github.com/users/mcollina/followers","following_url":"https://api.github.com/users/mcollina/following{/other_user}","gists_url":"https://api.github.com/users/mcollina/gists{/gist_id}","starred_url":"https://api.github.com/users/mcollina/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mcollina/subscriptions","organizations_url":"https://api.github.com/users/mcollina/orgs","repos_url":"https://api.github.com/users/mcollina/repos","events_url":"https://api.github.com/users/mcollina/events{/privacy}","received_events_url":"https://api.github.com/users/mcollina/received_events","type":"User","site_admin":false},"labels":[{"id":326905670,"url":"https://api.github.com/repos/nodejs/node/labels/performance","name":"performance","color":"5319e7","default":false},{"id":441404503,"url":"https://api.github.com/repos/nodejs/node/labels/v7.x","name":"v7.x","color":"fbca04","default":false},{"id":176191361,"url":"https://api.github.com/repos/nodejs/node/labels/V8","name":"V8","color":"0052cc","default":false}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":22,"created_at":"2016-11-16T09:30:28Z","updated_at":"2016-11-18T11:53:08Z","closed_at":null,"body":"* **Version**: v7 and master\r\n* **Platform**: Mac\r\n* **Subsystem**:\r\n\r\n`instanceof` checks has become almost *100 times slower* in Node v7+ (and current master) \r\n\r\n```js\r\nvar r = /hello/\r\n\r\nconsole.time('instanceof RegExp')\r\nfor (var i = 0; i < 100000000; i++) {\r\n  r instanceof RegExp\r\n}\r\nconsole.timeEnd('instanceof RegExp')\r\n\r\nvar o = {}\r\n\r\nconsole.time('instanceof Object')\r\nfor (var i = 0; i < 100000000; i++) {\r\n  o instanceof Object\r\n}\r\nconsole.timeEnd('instanceof Object')\r\n```\r\n\r\nIn node v6:\r\n```\r\n$ node instanceof.js\r\ninstanceof RegExp: 133.519ms\r\ninstanceof Object: 134.572ms\r\n```\r\n\r\nIn node v7:\r\n```\r\n$ node instanceof.js\r\ninstanceof RegExp: 9858.616ms\r\ninstanceof Object: 9839.696ms\r\n```\r\n\r\nI know this is a problem in V8, but I think it's good to track it here as well.\r\n\r\nv8 issue: https://bugs.chromium.org/p/v8/issues/detail?id=5640\r\n\r\ncc @fhinkel"},"comment":{"url":"https://api.github.com/repos/nodejs/node/issues/comments/261514868","html_url":"https://github.com/nodejs/node/issues/9634#issuecomment-261514868","issue_url":"https://api.github.com/repos/nodejs/node/issues/9634","id":261514868,"user":{"login":"fhinkel","id":101553,"avatar_url":"https://avatars.githubusercontent.com/u/101553?v=3","gravatar_id":"","url":"https://api.github.com/users/fhinkel","html_url":"https://github.com/fhinkel","followers_url":"https://api.github.com/users/fhinkel/followers","following_url":"https://api.github.com/users/fhinkel/following{/other_user}","gists_url":"https://api.github.com/users/fhinkel/gists{/gist_id}","starred_url":"https://api.github.com/users/fhinkel/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/fhinkel/subscriptions","organizations_url":"https://api.github.com/users/fhinkel/orgs","repos_url":"https://api.github.com/users/fhinkel/repos","events_url":"https://api.github.com/users/fhinkel/events{/privacy}","received_events_url":"https://api.github.com/users/fhinkel/received_events","type":"User","site_admin":false},"created_at":"2016-11-18T11:53:08Z","updated_at":"2016-11-18T11:53:08Z","body":"@natorian Can we backport performance improvements to 5.4 or only bug fixes? \r\n\r\nIf we can't backport it to V8, we can always cherry-pick the commits to Node. We probably want to wait a few days though, in case there are any issues with the commits. "}}
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