Return-Path: X-Original-To: apmail-hadoop-common-issues-archive@minotaur.apache.org Delivered-To: apmail-hadoop-common-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 9C541181F8 for ; Wed, 14 Oct 2015 06:11:05 +0000 (UTC) Received: (qmail 48436 invoked by uid 500); 14 Oct 2015 06:11:05 -0000 Delivered-To: apmail-hadoop-common-issues-archive@hadoop.apache.org Received: (qmail 48392 invoked by uid 500); 14 Oct 2015 06:11:05 -0000 Mailing-List: contact common-issues-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: common-issues@hadoop.apache.org Delivered-To: mailing list common-issues@hadoop.apache.org Received: (qmail 48366 invoked by uid 99); 14 Oct 2015 06:11:05 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 14 Oct 2015 06:11:05 +0000 Date: Wed, 14 Oct 2015 06:11:05 +0000 (UTC) From: "Walter Su (JIRA)" To: common-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HADOOP-12475) Replace guava Cache with ConcurrentHashMap for caching Connection in ipc Client MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/HADOOP-12475?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Walter Su updated HADOOP-12475: ------------------------------- Status: Patch Available (was: Open) > Replace guava Cache with ConcurrentHashMap for caching Connection in ipc Client > ------------------------------------------------------------------------------- > > Key: HADOOP-12475 > URL: https://issues.apache.org/jira/browse/HADOOP-12475 > Project: Hadoop Common > Issue Type: Sub-task > Components: conf, io, ipc > Reporter: Walter Su > Assignee: Walter Su > Attachments: HADOOP-12475.01.patch > > > quote [~daryn] from HADOOP-11772: > {quote} > CacheBuilder is obscenely expensive for concurrent map, and it requires generating unnecessary garbage even just to look up a key. Replace it with ConcurrentHashMap. > I identified this issue that impaired my own perf testing under load. The slowdown isn't just the sync. It's the expensive of Connection's ctor stalling other connections. The expensive of ConnectionId#equals causes delays. Synch'ing on connections causes unfair contention unlike a sync'ed method. Concurrency simply hides this. > {quote} > BTW, guava Cache is heavyweight. Per local test, ConcurrentHashMap has better overal performance. -- This message was sent by Atlassian JIRA (v6.3.4#6332)