This repository contains two independent projects, both related to the numerical simulations of systems modeled as Markov processes:

serverless (in Python): simulator of a serverless environment
markovsim (in C++): generic M/M/c simulator

serverless

A numerical tool to compute the steady-state average delay of clients in a serverless environment, where the servers behave as M/M/1 processes with Processor Sharing policy.

The network latency between every client and server is constant and can be set by the user.

The simulator assumes that every client is associated to exactly two servers and it collects a long-term average of the service delay, which is used to decide whether to switch to the secondary server to which it is assigned. In order to compare the delay between primary and secondary servers, it is also assumed that the client performs a fraction of its requests towards the secondary server (the fraction being equal for all clients and called Chi in code).

If you use this tool in your research, please cite as:

C. Cicconetti, M. Conti and A. Passarella, Uncoordinated access to serverless computing in MEC systems for IoT, Computer Networks, https://doi.org/10.1016/j.comnet.2020.107184

Dependencies

Uses Python 2.7. Requires numpy and scipy.

Unit tests

cd Serverless
python -m unittest test_steadystate.TestSteadyState

markovsim

A simple M/M/c simulator.

Dependencies

Requires C++-14 support. Uses uiiitsupport https://github.com/ccicconetti/support/. Tested on Mac OS X and Linux.

Build instructions

First, make sure you have CMake (version >= 3.2), a recent C++ compiler and all the dependencies installed:

glog
Boost

Very likely you can find packaged versions in your system's package repository.

Note that gmock is also needed to compile the unit tests but, if everything goes right, it will be downloaded automatically by CMake (needless to say: you do need a working Internet connection for this step).

git clone git@github.com:ccicconetti/markovsim.git
git submodule update --init --recursive

Once everything is ready (assuming clang++ is your compiler):

cd build/debug
../build.sh clang++
make

If you want to compile with optimizations and without assertions, change debug into release above. This will disable the compilation of the unit tests (see below).

Execution

After compilation, this shows the command-line options:

cd build/debug/Executables
./markovsim -h

Output:

Allowed options:
  -h [ --help ]                  produce help message
  --seed arg (=1567521176755220) Seed generator. If not specified use the
                                 number of seconds since Jan 1, 1970.
  --lambda arg (=1)              Arrival rate.
  --mu arg (=1)                  Serving rate.
  --c arg (=2)                   Number of servers.
  --warmup arg (=30)             The warm-up duration, in s.
  --duration arg (=60)           Simulation duration step, in s.
  --threshold arg (=0.001)       Convergence threshold, in s.
  --distributions arg            Write the full distributions on file with the
                                 given base name.

Unit tests

cd build/debug/Test/
./testmain