Return-Path: X-Original-To: archive-asf-public-internal@cust-asf2.ponee.io Delivered-To: archive-asf-public-internal@cust-asf2.ponee.io Received: from cust-asf.ponee.io (cust-asf.ponee.io [163.172.22.183]) by cust-asf2.ponee.io (Postfix) with ESMTP id 76547200BC7 for ; Fri, 11 Nov 2016 02:11:00 +0100 (CET) Received: by cust-asf.ponee.io (Postfix) id 744C4160B15; Fri, 11 Nov 2016 01:11:00 +0000 (UTC) Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by cust-asf.ponee.io (Postfix) with SMTP id 9DA1C160B01 for ; Fri, 11 Nov 2016 02:10:59 +0100 (CET) Received: (qmail 98347 invoked by uid 500); 11 Nov 2016 01:10:58 -0000 Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list hdfs-issues@hadoop.apache.org Received: (qmail 98320 invoked by uid 99); 11 Nov 2016 01:10:58 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Fri, 11 Nov 2016 01:10:58 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id 9C50C2C2B10 for ; Fri, 11 Nov 2016 01:10:58 +0000 (UTC) Date: Fri, 11 Nov 2016 01:10:58 +0000 (UTC) From: "Arpit Agarwal (JIRA)" To: hdfs-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HDFS-9668) Optimize the locking in FsDatasetImpl MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 archived-at: Fri, 11 Nov 2016 01:11:00 -0000 [ https://issues.apache.org/jira/browse/HDFS-9668?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15655727#comment-15655727 ] Arpit Agarwal commented on HDFS-9668: ------------------------------------- Hi [~jingcheng.du@intel.com] I started taking a look at [the patch|https://issues.apache.org/jira/secure/attachment/12837702/HDFS-9668-23.patch]. A few early comments: # Can we separate the block-lock addition from the read-write lock? In the first patch we should focus on converting the exclusive lock to a read-write lock only. I can help split up the patch if you'd like. # DirectoryScanner.java:391 - We can just get the read lock here. This phase of the directory scanner makes no changes to the DataNode state. # FsDatasetImpl.java:1117 - This should get the write lock as it calls appendImpl which modifies the volumeMap. # FsDatasetImpl.java:1268 - This too calls appendImpl, so it should get the write lock. Still reviewing FsDatasetImpl further... Also you can probably hold off on the branch-2 patch until we finalize the trunk changes. > Optimize the locking in FsDatasetImpl > ------------------------------------- > > Key: HDFS-9668 > URL: https://issues.apache.org/jira/browse/HDFS-9668 > Project: Hadoop HDFS > Issue Type: Improvement > Components: datanode > Reporter: Jingcheng Du > Assignee: Jingcheng Du > Attachments: HDFS-9668-1.patch, HDFS-9668-10.patch, HDFS-9668-11.patch, HDFS-9668-12.patch, HDFS-9668-13.patch, HDFS-9668-14.patch, HDFS-9668-14.patch, HDFS-9668-15.patch, HDFS-9668-16.patch, HDFS-9668-17.patch, HDFS-9668-18.patch, HDFS-9668-19.patch, HDFS-9668-19.patch, HDFS-9668-2.patch, HDFS-9668-20.patch, HDFS-9668-21.patch, HDFS-9668-22.patch, HDFS-9668-23.patch, HDFS-9668-23.patch, HDFS-9668-3.patch, HDFS-9668-4.patch, HDFS-9668-5.patch, HDFS-9668-6.patch, HDFS-9668-7.patch, HDFS-9668-8.patch, HDFS-9668-9.patch, execution_time.png > > > During the HBase test on a tiered storage of HDFS (WAL is stored in SSD/RAMDISK, and all other files are stored in HDD), we observe many long-time BLOCKED threads on FsDatasetImpl in DataNode. The following is part of the jstack result: > {noformat} > "DataXceiver for client DFSClient_NONMAPREDUCE_-1626037897_1 at /192.168.50.16:48521 [Receiving block BP-1042877462-192.168.50.13-1446173170517:blk_1073779272_40852]" - Thread t@93336 > java.lang.Thread.State: BLOCKED > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.createRbw(FsDatasetImpl.java:1111) > - waiting to lock <18324c9> (a org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl) owned by "DataXceiver for client DFSClient_NONMAPREDUCE_-1626037897_1 at /192.168.50.16:48520 [Receiving block BP-1042877462-192.168.50.13-1446173170517:blk_1073779271_40851]" t@93335 > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.createRbw(FsDatasetImpl.java:113) > at org.apache.hadoop.hdfs.server.datanode.BlockReceiver.(BlockReceiver.java:183) > at org.apache.hadoop.hdfs.server.datanode.DataXceiver.writeBlock(DataXceiver.java:615) > at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.opWriteBlock(Receiver.java:137) > at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.processOp(Receiver.java:74) > at org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:235) > at java.lang.Thread.run(Thread.java:745) > Locked ownable synchronizers: > - None > > "DataXceiver for client DFSClient_NONMAPREDUCE_-1626037897_1 at /192.168.50.16:48520 [Receiving block BP-1042877462-192.168.50.13-1446173170517:blk_1073779271_40851]" - Thread t@93335 > java.lang.Thread.State: RUNNABLE > at java.io.UnixFileSystem.createFileExclusively(Native Method) > at java.io.File.createNewFile(File.java:1012) > at org.apache.hadoop.hdfs.server.datanode.DatanodeUtil.createTmpFile(DatanodeUtil.java:66) > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.BlockPoolSlice.createRbwFile(BlockPoolSlice.java:271) > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl.createRbwFile(FsVolumeImpl.java:286) > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.createRbw(FsDatasetImpl.java:1140) > - locked <18324c9> (a org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl) > at org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.createRbw(FsDatasetImpl.java:113) > at org.apache.hadoop.hdfs.server.datanode.BlockReceiver.(BlockReceiver.java:183) > at org.apache.hadoop.hdfs.server.datanode.DataXceiver.writeBlock(DataXceiver.java:615) > at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.opWriteBlock(Receiver.java:137) > at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.processOp(Receiver.java:74) > at org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:235) > at java.lang.Thread.run(Thread.java:745) > Locked ownable synchronizers: > - None > {noformat} > We measured the execution of some operations in FsDatasetImpl during the test. Here following is the result. > !execution_time.png! > The operations of finalizeBlock, addBlock and createRbw on HDD in a heavy load take a really long time. > It means one slow operation of finalizeBlock, addBlock and createRbw in a slow storage can block all the other same operations in the same DataNode, especially in HBase when many wal/flusher/compactor are configured. > We need a finer grained lock mechanism in a new FsDatasetImpl implementation and users can choose the implementation by configuring "dfs.datanode.fsdataset.factory" in DataNode. > We can implement the lock by either storage level or block-level. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org