60f3ade82b
Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything. Reviewed-by: jwilhelm, brutisso
README:
This file should be located at the top of the OpenJDK Mercurial root
repository. A full OpenJDK repository set (forest) should also include
the following 7 nested repositories:
"jdk", "hotspot", "langtools", "nashorn", "corba", "jaxws" and "jaxp".
The root repository can be obtained with something like:
hg clone http://hg.openjdk.java.net/jdk9/jdk9 openjdk9
You can run the get_source.sh script located in the root repository to get
the other needed repositories:
cd openjdk9 && sh ./get_source.sh
People unfamiliar with Mercurial should read the first few chapters of
the Mercurial book: http://hgbook.red-bean.com/read/
See http://openjdk.java.net/ for more information about OpenJDK.
Simple Build Instructions:
0. Get the necessary system software/packages installed on your system, see
http://hg.openjdk.java.net/jdk9/jdk9/raw-file/tip/README-builds.html
1. If you don't have a jdk8 or newer jdk, download and install it from
http://java.sun.com/javase/downloads/index.jsp
Add the /bin directory of this installation to your PATH environment
variable.
2. Configure the build:
bash ./configure
3. Build the OpenJDK:
make all
The resulting JDK image should be found in build/*/images/j2sdk-image
where make is GNU make 3.81 or newer, /usr/bin/make on Linux usually
is 3.81 or newer. Note that on Solaris, GNU make is called "gmake".
Complete details are available in the file:
http://hg.openjdk.java.net/jdk9/jdk9/raw-file/tip/README-builds.html