https://github.com/pmem/llpl
Low Level Persistence Library
https://github.com/pmem/llpl
java persistent-memory pmdk transactions
Last synced: 6 months ago
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Low Level Persistence Library
- Host: GitHub
- URL: https://github.com/pmem/llpl
- Owner: pmem
- License: other
- Created: 2018-05-29T21:54:56.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2023-05-09T18:38:15.000Z (over 2 years ago)
- Last Synced: 2024-04-28T02:42:32.837Z (over 1 year ago)
- Topics: java, persistent-memory, pmdk, transactions
- Language: Java
- Homepage:
- Size: 497 KB
- Stars: 97
- Watchers: 9
- Forks: 39
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
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README
# PROJECT NOT UNDER ACTIVE MANAGEMENT #
This project will no longer be maintained by Intel.
This project has been identified as having known security escapes.
Intel has ceased development and contributions including, but not limited to, maintenance, bug fixes, new releases, or updates, to this project.
Intel no longer accepts patches to this project.
# Low-Level Persistence Library #
## OVERVIEW ##
The Low-Level Persistence Library (LLPL) is a Java library that provides access to off-heap persistent memory.
LLPL includes several kinds of components that can be allocated and used alone or together in building applications:
* heaps: a pool of memory and an allocator for it
* memory blocks: unstructured bytes that can be laid out for any purpose and linked to build data structures
* pre-built data structures: arrays, linked list, and radix trees
* memory pools: a process-shareable pool of memory
Data stored in the components above can persist beyond the life of a JVM instance, i.e. across application or system restarts.
LLPL provides APIs that help developers ensure consistency of stored data.
Memory allocated using LLPL is not garbage-collected and must be explicitly deallocated using LLPL APIs.
LLPL uses the Persistent Memory Development Kit (PMDK).
For more information on PMDK, please visit http://pmem.io and https://github.com/pmem/pmdk.
## HOW TO BUILD & RUN ##
### PREREQUISITES TO BUILD ###
The following are the prerequisites for building this Java library:
1. Linux operating system
2. Persistent Memory Development Kit (PMDK) v1.5 or newer
3. Java 8 or newer
4. Build tools - `g++` compiler, `CMake` and `Maven`
### PREREQUISITES TO RUN ###
This library assumes the availability of hardware persistent memory or emulated persistent memory.
Instructions for creating emulated persistent memory are shown below.
### EMULATING PERSISTENT MEMORY ###
The preferred way is to create an in-memory DAX file system. This requires Linux kernel 4.2 or
greater. Please follow the steps at:
http://pmem.io/2016/02/22/pm-emulation.html
Alternatively, for use with older kernels, create a tmpfs partition as follows (as root):
```
$ mount -t tmpfs -o size=4G tmpfs /mnt/mem # creates a 4GB tmpfs partition
$ chmod -R a+rw /mnt/mem # enables read/write permissions to all users
```
### STEPS TO BUILD AND RUN TESTS ###
Once all the prerequisites have been satisfied:
```
$ git clone https://github.com/pmem/llpl.git
$ cd llpl
$ mvn test -Dtest.heap.path=
```
Available Maven commands include:
- `compile` - builds sources
- `test` - builds and runs tests
- `javadoc:javadoc` - builds javadocs into ```target/site/apidocs```
- `package` - builds jar file into ```target``` directory
### USING THIS LIBRARY IN EXISTING JAVA APPLICATIONS ###
#### WITH MAVEN ####
LLPL is available from the Maven central repository. Add the following dependency to your pom.xml:
```
com.intel.pmem
llpl
1.2.1-release
jar
```
#### WITH CLASSPATH ####
To use this library in your Java application, build the LLPL jar and include
its location in your Java classpath. For example:
```
$ mvn package
$ javac -cp .:/llpl/target/llpl-.jar
$ java -cp .:/llpl/target/llpl-.jar
```
Alternatively, include LLPL's `target/classes` directory in your Java classpath and the
`target/cppbuild` directory in your `java.library.path`. For example:
```
$ mvn compile
$ javac -cp .:/llpl/target/classes
$ java -cp .:/llpl/target/classes -Djava.library.path=/llpl/target/cppbuild
```
## CONTRIBUTING ##
Thanks for your interest! Please see the CONTRIBUTING.md document for information on how to contribute.
We would love to hear your comments and suggestions via https://github.com/pmem/llpl/issues.
## Contacts ##
For more information on this library, contact Olasoji Denloye (olasoji.denloye@intel.com), Matt Welch (matt.welch@intel.com), or Steve Dohrmann (steve.dohrmann@intel.com).