view agent/doc/ReadMe-JavaScript.text @ 12110:4c84d351cca9

8007074: SIGSEGV at ParMarkBitMap::verify_clear() Summary: Replace the broken large pages implementation on Linux. New flag: -XX:+UseTransparentHugePages - Linux specific flag to turn on transparent huge page hinting with madvise(..., MAP_HUGETLB). Changed behavior: -XX:+UseLargePages - tries to use -XX:+UseTransparentHugePages before trying other large pages implementations (on Linux). Changed behavior: -XX:+UseHugeTLBFS - Use upfront allocation of Large Pages instead of using the broken implementation to dynamically committing large pages. Changed behavior: -XX:LargePageSizeInBytes - Turned off the ability to use this flag on Linux and provides warning to user if set to a value different than the OS chosen large page size. Changed behavior: Setting no large page size - Now defaults to use -XX:UseTransparentHugePages if the OS supports it. Previously, -XX:+UseHugeTLBFS was chosen if the OS was configured to use large pages. Reviewed-by: tschatzl, dcubed, brutisso
author stefank
date Fri, 16 Aug 2013 13:22:32 +0200
parents a61af66fc99e
children
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The HotSpot Serviceability Agent (SA) is a debugger for hotspot core
dumps and hung processes. There is a read-only JDI (Java Debugger
Interface) implementation on top of SA. This is part of JDK product and
the classes are in $JDK/tools/sa-jdi.jar.

In addition, there are few serviceability tools in $JDK/bin, namely,
jstack (java stack trace tool), jmap (heap tool), jinfo (Java config
tool) and jsadebugd. The classes for these are also in sa-jdi.jar
file. sa-jdi.jar file is built along with hotspot (libjvm.so) on Solaris
and Linux platforms. On Windows platform, SA-JDI is not included and
serviceability tools do not use SA.

Apart from these, HotSpot SA consists of a number of tools that are
*not* included in JDK product bits.

The sources and makefile for all-of-SA (including non-productized stuff)
are under $HOTSPOT_WS/agent directory. The makefile $HOTSPOT/agent/make
directory and shell scripts (and batch files) are used to build and run
SA non-product tools. There is also documentation of SA under
$HOTSPOT/agent/doc directory.

To build complete SA, you need to have Rhino Mozilla jar (js.jar)
version 1.5R5 under $HOTSPOT/agent/src/share/lib directory. Rhino is
JavaScript interpreter written in Java. Rhino is used to implement SA
features such as

* SA command line debugger's JavaScript interface
 - refer to $HOTSPOT/agent/doc/clhsdb.html
 - refer to $HOTSPOT/agent/doc/jsdb.html
* SA simple object query language (SOQL) 
 - language to query Java heap. 

Rhino's "js.jar" is not included in hotspot source bundles. You need to
download it from http://www.mozilla.org/rhino/download.html.
 
Without js.jar, $HOTSPOT/agent/make/Makefile will fail to build. But,
note that sa-jdi.jar containing the productized portions of SA will
still be built when you build hotspot JVM.