Bug 1383394

Summary:	OpenJDK should default to -XX:+AssumeMP
Product:	Red Hat Enterprise Linux 7	Reporter:	Andrew Haley <aph>
Component:	java-1.8.0-openjdk	Assignee:	Andrew John Hughes <ahughes>
Status:	CLOSED CURRENTRELEASE	QA Contact:	BaseOS QE - Apps <qe-baseos-apps>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.4	CC:	ahughes, jvanek
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:	java-1.8.0-openjdk-1.8.0.111-2.b15.el7_3	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-11-15 03:55:31 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Andrew Haley 2016-10-10 14:14:00 UTC

The number of configures processors can change while a process is running.  If OpenJDK starts with 1 processor and more are added, code is compiled without memory barriers in locks.  This leads to odd behaviour and crashes.

We should always assume that we're running on a multiprocessor system.  This means that we default to safety, but if someone really needs the best performance on a single-core system they can use -XX:-AssumeMP .  RHEL is not certified for single-core usage anyway.

Comment 2 Andrew John Hughes 2016-11-15 03:55:31 UTC

Closing this as fixed in the current z-stream release.