# performance_measuring

Scripts and tools to measure performance.

This repo meant to be a sandbox.

## The tested dummy algorithm

The measured algorithms are 3 variations on *counting the smallest element in a array*.

 * C style, count-as-go: O(n)
 * C++ `std::min_element` then `std::count`: O(n) + O(n)
 * C++ `std::sort` then `std::upper_bound`: O(n log n) + O(n)

## Environment

The array contains 10k randomly generated integers [0, 1000].

The machine which generated the results is an [Intel NUC 7CJYH](https://www.intel.com/content/www/us/en/products/boards-kits/nuc/kits/nuc7cjyh.html).

## Catch2's benchmarking tools

Using [catch2](https://github.com/catchorg/Catch2), an example output of `performance_measuring_test`:

![tests.png](https://jenkins.matetelki.eu/job/gitea.matetelki.eu/job/performance_measuring/job/master/lastSuccessfulBuild/artifact/tests.png)

## Flamegraph

An interactive [flamegraph](https://github.com/brendangregg/FlameGraph) can be generated to visualize [perf](http://www.brendangregg.com/perf.html)'s measurements, where the callgraph can be traversed.

![flamegraph.svg](https://jenkins.matetelki.eu/job/gitea.matetelki.eu/job/performance_measuring/job/master/lastSuccessfulBuild/artifact/flamegraph.svg)