Metall: A Persistent Memory Allocator For Data-Centric Analytics

Provides rich memory allocation interfaces for C++ applications that use persistent memory devices to persistently store heap data on such devices.
Creates files in persistent memory and maps them into virtual memory space so that users can access the mapped region just as normal memory regions allocated in DRAM.
Actual persistent memory hardware could be any non-volatile memory (NVM) with file system support.
To provide persistent memory allocation, Metall employs concepts and APIs developed by Boost.Interprocess.
Supports multi-thread
Also provides a space-efficient snapshot/versioning, leveraging reflink copy mechanism in filesystem. In case reflink is not supported, Metall automatically falls back to regular copy.
See details: Metall overview slides.

Getting Started

Metall consists of only header files and requires some header files in Boost C++ Libraries.

All core files exist under metall/include/metall/.

Required

GCC 8.1 or more (8.3 or more is recommended due to early implementation of the Filesystem library).

Build

Boost C++ Libraries 1.64 or more is required (build is not required; needs only their header files).

To build your program with Metall, all you have to do is just setting include paths such as '-I' or CPLUS_INCLUDE_PATH.

For example,

# Download Boost (Boost C++ Libraries 1.64 or more is required)
# One can skip this step if Boost is already available.
wget https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.tar.gz
tar xvf boost_1_75_0.tar.gz
export BOOST_ROOT=$PWD/boost_1_75_0

git clone https://github.com/LLNL/metall
export METALL_INCLUDE=$PWD/metall/include

g++ -std=c++17 your_program.cpp -lstdc++fs -I${BOOST_ROOT} -I${METALL_INCLUDE}

Unofficial Support For Clang

Clang can be used instead of GCC to build Metall. However, we haven't tested it intensively. Also, Boost C++ Libraries 1.69 or more may be required if one wants to build Metall with Clang + CUDA.

Metall with Spack

Metall package is also available on Spack.

As Metall depends on Boost C++ Libraries, Spack also installs a proper version of Boost C++ Libraries automatically, if needed.

# Install Metall and Boost C++ Libraries
spack install metall

# Sets environment variables: BOOST_ROOT and METALL_ROOT.
# Boost C++ Libraries and Metall are installed at the locations, respectively.
spack load metall

# Build a program that uses Metall
# Please note that one has to put 'include' at the end of BOOST_ROOT and METALL_ROOT
g++ -std=c++17 your_program.cpp -lstdc++fs -I${BOOST_ROOT}/include -I${METALL_ROOT}/include

Build Examples

Metall repository contains some example programs under example directory. One can use CMake to build the examples. For more details, see a page here.

Documentation

Full documentation is available.

Generate API document using Doxygen

A Doxygen configuration file is here.

To generate API document:

cd metall
mkdir build_doc
cd build_doc
doxygen ../docs/Doxyfile.in

Publication

Metall: A Persistent Memory Allocator Enabling Graph Processing

Paper PDF

IEEE Xplore

About

Authors

Keita Iwabuchi (kiwabuchi at llnl dot gov)
Roger A Pearce (rpearce at llnl dot gov)
Maya B Gokhale (gokhale2 at llnl dot gov).

License

Metall is distributed under the terms of both the MIT license and the Apache License (Version 2.0). Users may choose either license, at their option.

All new contributions must be made under both the MIT and Apache-2.0 licenses.

See LICENSE-MIT, LICENSE-APACHE, NOTICE, and COPYRIGHT for details.

SPDX-License-Identifier: (Apache-2.0 OR MIT)

Release

LLNL-CODE-768617

KIwabuchi/metall