Updating the readme file

README.md

@@ -1,3 +1,31 @@
 # performance_measuring
 
-Scripts and tools to measure performance.
+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)