MAT is a simple memory analysis tool intended to help understand where the memory is used in a program.
The tool works by using a small shared library that
can be loaded by using the LD_PRELOAD
dynamic linker option.
The shared library collects memory allocation events and
generates an event file that can be analyzed by MAT tool.
From the event file, the tool is able to provide useful information. This includes the details about the memory allocation (size, address), the complete stack frame where the memory allocation was made, the timestamp and thread information.
MAT was created to answer these simple questions:
- where is my memory used?
- what is the size of data structures and their impact on the global memory?
- what function or area of my program is using the most memory?
It is similar to the Massif heap profiler provided by a Valgrind plugin.
A first version of MAT existed back in 1994 but it was written in C++ when Valgrind was not available.
- Update the build process
- Update for Ada Utility Library 2.6.0 and Ada BFD 1.3.0
- Add support to analyze GNAT Ada compiler secondary stack allocations
- Update for binutils 2.34 and Ada BFD
- Update for Ada Utility Library 2.4.0
- Fix monitoring of
calloc
with glibc - Add colors in mat analysis
The project uses git submodules to integrate several other projects. To get all the sources, use the following commands:
git clone --recursive https://github.com/stcarrez/mat.git
cd mat
The package is composed of three separate components:
libmat
is the shared library that instruments the memory allocation.matl
is a small launcher that helps instrument a program with libmat.mat
is the analysis tool.
libmat
and matl
are written in C and mat
is written in Ada which requires
the GNAT Ada compiler. By default the mat
component is not built.
If you only need libmat
and matl
, configure and build as follows:
./configure
make
To build a 32-bit or 64-bit version of the shared library you may use:
CC="/usr/bin/gcc -m32" ./configure --disable-mat
make
or
CC="/usr/bin/gcc -m64" ./configure --disable-mat
make
If you're using a cross compilation environment, you should indicate to the configure your target host. For example to build for a remote mips system, use:
./configure --host="mips-uclibc-linux" --target=mips-uclibc-linux --disable-mat
make
To build the mat
analysis tool, you must have installed the following
components on your system:
- the GNAT Ada compiler (at least 4.7.3 or higher),
- the GNU Ada Bfd library (https://github.com/stcarrez/ada-bfd.git),
- the Ada Utility Library (https://github.com/stcarrez/ada-util.git)
On Debian-based systems, you may have to install the following packages:
sudo apt-get install gnat gprbuild binutils-dev libiberty-dev libreadline-dev
If you have not installed Ada Utility Library and Ada Bfd Library on your system, you can configure and build by using:
./configure --enable-ada-util --enable-ada-bfd
make
You can instrument your application passively by recording all events and looking at the memory allocation after the program has stopped. It is also possible to instrument dynamically while the application is running. Both methods have they advantages.
You can instrument the memory allocation by using the matl
launcher.
matl -o name my-program
While the program runs and the libmat.so collect events,
it generates a file name-<pid>.mat
.
Start mat
with the generated file:
mat name-xxx.mat
Once the memory events are loaded, you can use the interactive
commands to look at the events. The first commands you may use
are info
, timeline
and sizes
as they give a short summary
and analysis of the events.
The dynamic instrumentation requires that the mat
analyser is started in
the server mode: it is started first, before the application to analyse.
The server is activated by the -s
option. It listens to the TCP/IP port 4606
and then enter in the interactive mode:
mat -s
Then, you can launch your application through the same matl
launcher
but you will specify the host name to connect:
matl -s localhost my-program
On embedded systems, you only need to build the libmat.so and matl parts. For Mips and ARM, for the backtrace to work, you should compile your program with the -funwind-tables gcc option. Instrument your program and copy the generated .mat files on your Linux host. Make sure your program is not stripped and available to the mat program to get the symbols (use the -s path option if necessary).