Return-Path: X-Original-To: apmail-hadoop-hdfs-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-issues-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 542847AC9 for ; Sat, 8 Oct 2011 16:34:51 +0000 (UTC) Received: (qmail 95705 invoked by uid 500); 8 Oct 2011 16:34:51 -0000 Delivered-To: apmail-hadoop-hdfs-issues-archive@hadoop.apache.org Received: (qmail 95679 invoked by uid 500); 8 Oct 2011 16:34:51 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: hdfs-issues@hadoop.apache.org Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 95671 invoked by uid 99); 8 Oct 2011 16:34:51 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 08 Oct 2011 16:34:51 +0000 X-ASF-Spam-Status: No, hits=-2000.5 required=5.0 tests=ALL_TRUSTED,RP_MATCHES_RCVD X-Spam-Check-By: apache.org Received: from [140.211.11.116] (HELO hel.zones.apache.org) (140.211.11.116) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 08 Oct 2011 16:34:50 +0000 Received: from hel.zones.apache.org (hel.zones.apache.org [140.211.11.116]) by hel.zones.apache.org (Postfix) with ESMTP id B1D642AF7B2 for ; Sat, 8 Oct 2011 16:34:29 +0000 (UTC) Date: Sat, 8 Oct 2011 16:34:29 +0000 (UTC) From: "Hairong Kuang (Created) (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: <569485428.11789.1318091669729.JavaMail.tomcat@hel.zones.apache.org> Subject: [jira] [Created] (HDFS-2421) Improve the concurrency of SerialNumberMap in NameNode MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 Improve the concurrency of SerialNumberMap in NameNode ------------------------------------------------------- Key: HDFS-2421 URL: https://issues.apache.org/jira/browse/HDFS-2421 Project: Hadoop HDFS Issue Type: Improvement Components: name-node Reporter: Hairong Kuang Assignee: Weiyan Wang Fix For: 0.24.0 After enabled permission checking in our HDFS test cluster, our benchmark observed a significant reduced concurrency in NameNode. Investigation showed that most threads were blocked at acquiring the lock of org.apache.hadoop.hdfs.server.namenode.SerialNumberManager$SerialNumberMap. We used concurrentHashMap to replace Hashmap + synchronized methods, which greatly improved the situation. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira