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 T h r e a d   M o n i t o r i n g   T o o l

TMT: Thread Monitoring Tool

TMT is a lightweight C++ tool that leverages eBPF to trace and analyze how many threads a target application creates and uses during its execution.

It captures scheduling and process events directly from the kernel and exports structured data for post-processing and visualization.

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Build

Make sure you have:

• Linux kernel with eBPF support
• clang
• libbpf development files
• cmake
• (optional, for plots) gnuplot

To build the logger:

cmake -S . -B build
cmake --build build

This will produce the tmt_logger binary under:

build/bin/tmt_logger

and all compiled eBPF programs under:

build/bin/*.bpf.o

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Usage

To monitor an application with TMT, run:

sudo build/bin/tmt_logger --cmd "<command to trace>" [--print-raw]

Examples

sudo build/bin/tmt_logger --cmd "sleep 1"

sudo build/bin/tmt_logger --cmd "python3 thread_test.py" --print-raw

Options

• --cmd "<program>" — command to execute and trace (required)
• --print-raw — print raw kernel events as they are received

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Output

By default, TMT will generate several files under the out/ directory in the project root:

• out/alive_series.csv — timeline of active threads per process
• out/oncpu_slices.csv — CPU scheduling slices

On the terminal, you will also see a "Top runtime per CPU" summary.

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Plots & Visualization

TMT can generate ready-to-use plots using gnuplot (if available).

Requirements

• gnuplot installed and visible in PATH
• CMake option TMT_ENABLE_PLOTS enabled (ON by default)

If you want to be explicit:

cmake -S . -B build -DTMT_ENABLE_PLOTS=ON
cmake --build build

Generating plots

After you have run tmt_logger at least once (so that out/alive_series.csv and out/oncpu_slices.csv exist), you can generate the plots via CMake custom targets.

From the build directory:

cmake --build build --target plot_threads_over_time

This will run gnuplot with the script under plots/threads_over_time.gp and produce:

• out/threads_over_time.png — visual summary of:
  • thread activity over time (alive threads)
  • CPU scheduling slices aggregated over the timeline

To generate all available plots:

cmake --build build --target plots_all

If gnuplot is not installed, the plots_all target will simply print a message reminding you to install it and reconfigure.

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Quickstart

1. Configure & build

   cmake -S . -B build -DTMT_ENABLE_PLOTS=ON
   cmake --build build

2. Run a trace

   sudo build/bin/tmt_logger --cmd "python3 thread_test.py"

3. Generate plots

   cmake --build build --target plots_all

   Then open out/threads_over_time.png with your favorite image viewer.

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Acknowledgements

TMT was originally developed by
Stefano Monaldi
and is now maintained by
Marco Edoardo Santimaria,
Robert Birke and
Cosmin Stoica.