🔍 Metafor: Analyzing Metastability in Server Systems

Metafor is a Python-based tool designed to analyze metastability in server systems by modeling them as continuous-time Markov chains (CTMCs). It provides analytical and visual tools to explore long transient behaviors, steady states, and mixing properties.

⚙️ Prerequisites

Ensure you have Python 3.10 or later installed on your machine.

📦 Installing Metafor

To install the required Python packages and set up your environment, run the following commands:

python3 -m venv .venv
source .venv/bin/activate
pip install .
export PYTHONPATH=/path/to/metafor:/path/to/metafor/metafor

Replace /path/to/metafor with the actual path to your local clone of the Metafor repository.

🚀 Example: Single-Threaded Single Server System

Below is an example where a single-threaded server handles requests at an average rate of ( \mu = 10 ) requests per second (RPS). A client sends requests at ( \lambda = 9.5 ) RPS, each with a timeout of 3 seconds and a maximum of 4 retries.

from metafor.dsl.dsl import Server, Work, Source, Program
from metafor.analysis.visualize import Visualizer

# Define server processing rate
api = {"insert": Work(10, [])}

# Configure server parameters: queue size, orbit size, threads
server = Server("52", api, qsize=100, orbit_size=20, thread_pool=1)

# Define client request behavior
src = Source("client", "insert", 9.5, timeout=3, retries=4)

# Build the request-response system
p = Program("Service52")
p.add_server(server)
p.add_source(src)
p.connect("client", "52")

📊 Running Basic Analysis

To compute key system metrics such as the average steady-state queue size, sorted eigenvalues of the CTMC, mixing time, and expected hitting time from full to empty queue:

basic_stats(p)

🧭 Visualizing the CTMC

To visualize the underlying CTMC and identify potential metastable behavior:

v = Visualizer(program())
v.visualize(show_equilibrium=True)

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Feel free to modify this example or plug in more complex workloads and topologies using Metafor's flexible DSL and analysis tools.

✉️ Contact

For questions, feedback, or collaboration inquiries, feel free to reach out to [email protected].