# Performance analysis (2D FDTD)

**Performance analysis** connects measured simulation cost with an explanation of where time is spent. The project separates benchmark samples, profiling, and report generation:

```bash
$ cp config.example config
$ make bench
$ make profile
$ make report
```

Edit `config` before running the sweep. Keep grid size, steps, precision, boundary, and snapshot frequency fixed when comparing execution backends or variants.

[[fdtd-cuda-benchmarking|Benchmarks]] record timing and throughput. [[fdtd-cuda-profiling|Profiles]] investigate expensive operations, while the traffic model estimates effective memory bandwidth. `make report` combines the selected measurements under `results/reports/`, with PDF output when available.

Small grids can expose launch or barrier overhead; large grids can pressure memory. Measurements identify the change, while profiles and counters help determine its cause.