{"action":"created","issue":{"url":"https://api.github.com/repos/apache/spark/issues/6323","labels_url":"https://api.github.com/repos/apache/spark/issues/6323/labels{/name}","comments_url":"https://api.github.com/repos/apache/spark/issues/6323/comments","events_url":"https://api.github.com/repos/apache/spark/issues/6323/events","html_url":"https://github.com/apache/spark/pull/6323","id":79090554,"number":6323,"title":"[SPARK-7795] [Core] Speed up task scheduling in standalone mode by reusing serializer","user":{"login":"coolfrood","id":5747419,"avatar_url":"https://avatars.githubusercontent.com/u/5747419?v=3","gravatar_id":"","url":"https://api.github.com/users/coolfrood","html_url":"https://github.com/coolfrood","followers_url":"https://api.github.com/users/coolfrood/followers","following_url":"https://api.github.com/users/coolfrood/following{/other_user}","gists_url":"https://api.github.com/users/coolfrood/gists{/gist_id}","starred_url":"https://api.github.com/users/coolfrood/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/coolfrood/subscriptions","organizations_url":"https://api.github.com/users/coolfrood/orgs","repos_url":"https://api.github.com/users/coolfrood/repos","events_url":"https://api.github.com/users/coolfrood/events{/privacy}","received_events_url":"https://api.github.com/users/coolfrood/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":8,"created_at":"2015-05-21T17:28:46Z","updated_at":"2015-05-21T18:03:03Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/apache/spark/pulls/6323","html_url":"https://github.com/apache/spark/pull/6323","diff_url":"https://github.com/apache/spark/pull/6323.diff","patch_url":"https://github.com/apache/spark/pull/6323.patch"},"body":"My experiments with scheduling very short tasks in standalone cluster mode indicated that a significant amount of time was being spent in scheduling the tasks (>500ms for 256 tasks).  I found that most of the time was being spent in creating a new instance of serializer for each task.  Changing this to just one serializer brought down the scheduling time to 8ms."},"comment":{"url":"https://api.github.com/repos/apache/spark/issues/comments/104373345","html_url":"https://github.com/apache/spark/pull/6323#issuecomment-104373345","issue_url":"https://api.github.com/repos/apache/spark/issues/6323","id":104373345,"user":{"login":"SparkQA","id":8108735,"avatar_url":"https://avatars.githubusercontent.com/u/8108735?v=3","gravatar_id":"","url":"https://api.github.com/users/SparkQA","html_url":"https://github.com/SparkQA","followers_url":"https://api.github.com/users/SparkQA/followers","following_url":"https://api.github.com/users/SparkQA/following{/other_user}","gists_url":"https://api.github.com/users/SparkQA/gists{/gist_id}","starred_url":"https://api.github.com/users/SparkQA/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/SparkQA/subscriptions","organizations_url":"https://api.github.com/users/SparkQA/orgs","repos_url":"https://api.github.com/users/SparkQA/repos","events_url":"https://api.github.com/users/SparkQA/events{/privacy}","received_events_url":"https://api.github.com/users/SparkQA/received_events","type":"User","site_admin":false},"created_at":"2015-05-21T18:03:03Z","updated_at":"2015-05-21T18:03:03Z","body":"  [Test build #33259 has started](https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/33259/consoleFull) for   PR 6323 at commit [`fe530cd`](https://github.com/apache/spark/commit/fe530cddae1cb573387f7fc1eb344513c91d69bb)."}}