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 E43E31768A for ; Mon, 26 Jan 2015 19:46:34 +0000 (UTC) Received: (qmail 72037 invoked by uid 500); 26 Jan 2015 19:46:35 -0000 Delivered-To: apmail-hadoop-common-issues-archive@hadoop.apache.org Received: (qmail 71989 invoked by uid 500); 26 Jan 2015 19:46:35 -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 71977 invoked by uid 99); 26 Jan 2015 19:46:35 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 26 Jan 2015 19:46:35 +0000 Date: Mon, 26 Jan 2015 19:46:34 +0000 (UTC) From: "Suman Somasundar (JIRA)" To: common-issues@hadoop.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Updated] (HADOOP-11466) FastByteComparisons: do not use UNSAFE_COMPARER on the SPARC architecture because it is slower there 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-11466?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Suman Somasundar updated HADOOP-11466: -------------------------------------- Attachment: (was: HADOOP-11466.002.patch) > FastByteComparisons: do not use UNSAFE_COMPARER on the SPARC architecture because it is slower there > ---------------------------------------------------------------------------------------------------- > > Key: HADOOP-11466 > URL: https://issues.apache.org/jira/browse/HADOOP-11466 > Project: Hadoop Common > Issue Type: Improvement > Components: io, performance, util > Environment: Linux X86 and Solaris SPARC > Reporter: Suman Somasundar > Assignee: Suman Somasundar > Priority: Minor > Labels: patch > Fix For: 2.6.1 > > Attachments: HADOOP-11466.003.patch > > > One difference between Hadoop 2.x and Hadoop 1.x is a utility to compare two byte arrays at coarser 8-byte granularity instead of at the byte-level. The discussion at HADOOP-7761 says this fast byte comparison is somewhat faster for longer arrays and somewhat slower for smaller arrays ( AVRO-939). In order to do 8-byte reads on addresses not aligned to 8-byte boundaries, the patch uses Unsafe.getLong. The problem is that this call is incredibly expensive on SPARC. The reason is that the Studio compiler detects an unaligned pointer read and handles this read in software. x86 supports unaligned reads, so there is no penalty for this call on x86. -- This message was sent by Atlassian JIRA (v6.3.4#6332)