Return-Path: X-Original-To: apmail-hbase-issues-archive@www.apache.org Delivered-To: apmail-hbase-issues-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 3881F18218 for ; Tue, 29 Dec 2015 23:34:50 +0000 (UTC) Received: (qmail 96040 invoked by uid 500); 29 Dec 2015 23:34:49 -0000 Delivered-To: apmail-hbase-issues-archive@hbase.apache.org Received: (qmail 95936 invoked by uid 500); 29 Dec 2015 23:34:49 -0000 Mailing-List: contact issues-help@hbase.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Delivered-To: mailing list issues@hbase.apache.org Received: (qmail 95885 invoked by uid 99); 29 Dec 2015 23:34:49 -0000 Received: from arcas.apache.org (HELO arcas) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 29 Dec 2015 23:34:49 +0000 Received: from arcas.apache.org (localhost [127.0.0.1]) by arcas (Postfix) with ESMTP id 9D4832C1F5A for ; Tue, 29 Dec 2015 23:34:49 +0000 (UTC) Date: Tue, 29 Dec 2015 23:34:49 +0000 (UTC) From: "stack (JIRA)" To: issues@hbase.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (HBASE-15047) Try spin lock for MVCC completion 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/HBASE-15047?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15074434#comment-15074434 ] stack commented on HBASE-15047: ------------------------------- Radical. At first blush, we will be waiting too long in mvcc to spin and who says the currently scheduled thread is next in line for mvcc and what is to prevent all CPUs being here spinning with no thread free to make forward progess? I'll try it though. > Try spin lock for MVCC completion > --------------------------------- > > Key: HBASE-15047 > URL: https://issues.apache.org/jira/browse/HBASE-15047 > Project: HBase > Issue Type: Bug > Reporter: Elliott Clark > Assignee: Elliott Clark > Attachments: HBASE-15047.patch > > > Waits/Notify is very very expensive since it can cost a thread scheduling. There should only ever be a few threads ( < Num Cores ) running. So it should be possible to spin and use compare and swap to update the read point. -- This message was sent by Atlassian JIRA (v6.3.4#6332)