Brought to you by the High Performance and Dependable Computing Systems (HPDCS) at Sapienza, University of Rome
ROOT-Sim has evolved into a complex package ecosystem that forms a modern simulation framework. Therefore, for the 3.0 release, a single repository did not fit anymore, and ROOT-Sim has moved to the ROOT-Sim Organization. This repository has been archived for historical purposes, while the development of the simulation core is taking place in the ROOT-Sim core repository.
The ROme OpTimistic Simulator is an x86-64 Open Source, distributed multithreaded parallel
simulation library developed using C/POSIX technology. It transparently supports all the
mechanisms associated with parallelization and distribution of workload across the nodes
(e.g., mapping of simulation objects on different kernel instances) and
optimistic synchronization (e.g., state recoverability).
Distributed simulations rely on MPI3. In particular, global synchronization across
the different nodes relies on asynchronous MPI primitives, for increased efficiency.
The programming model supported by ROOT-Sim allows the simulation model developer
to use a simple application-callback function named ProcessEvent() as the event handler,
whose parameters determine which simulation object is currently taking control for
processing its next event, and where the state of this object is located in memory.
An object is a data structure, whose state can be scattered on dynamically allocated
memory chunks, hence the memory address passed to the callback locates a top level
data structure implementing the object state-layout.
ROOT-Sim's development started as a research project late back in 1987, and is currently maintained by the High Performance and Dependable Computing Systems group, a joint research group between Sapienza, University of Rome and University of Rome "Tor Vergata".
ROOT-Sim uses autotools to provide an installation workflow which is
common for all supported platforms. This repository does not provide
already-generated installation scripts (while released tarballs do),
rather we provide the convenience autogen.sh script which should
build everything on the target machine. Using autotools, autoconf,
automake and libtoolize are required to let autogen.sh generate
the correct configure script.
Briefly, the shell commands ./configure; make; make install should
configure, build, and install this package.
Also, you can also type make uninstall to remove the installed files.
By default, make install installs the package's commands under
/usr/local/bin, include files under /usr/local/include, etc. You
can specify an installation prefix other than /usr/local by giving
configure the option --prefix=PREFIX, where PREFIX must be an
absolute path name.
ROOT-Sim uses many gcc extensions, so the currently supported
compiler is only gcc.
For full configuration notes, and a discussion on the subsystems which this simulation library offers, please refer to the wiki.
When running make install, the rootsim-cc compiler is added to the path.
To compile a simulaton model, simply cd into the project's directory
and type rootsim-cc *.c -o model. This will create the model
executable, which is the model code already linked with the ROOT-sim library.
rootsim-cc ultimately relies on gcc, so any flag supported by
gcc can be passed to rootsim-cc.
To test the correctness of the model, it can be run sequentially, typing
./model --sequential --lp <number of required LPs>
This allows to spot errors in the implementation more easily.
Then, to run it in parallel, type
./model --wt <number of desired threads> --lp <number of required LPs>
To run in a distributed environment, you can use standard MPI commands,
such as:
mpiexec -n 2 --hostfile hosts --map-by node ./model --wt 2 --lp 16
This command runs the simulation model on two nodes (-n 2) specified in the
hosts file. Each node uses two concurrent threads (--wt 2). The simulation
involves 16 total Logical Processes (--lp 16).