Describe the default benchmark duration as an estimate

README.md

@@ -33,8 +33,9 @@ hyperfine 'sleep 0.3'
 ```
 
 Hyperfine will automatically determine the number of runs to perform for each command. By default,
-it will perform *at least* 10 benchmarking runs and measure for at least 3 seconds. To change this,
-you can use the `-r`/`--runs` option:
+it will perform *at least* 10 benchmarking runs and estimate a run count targeting roughly
+3 seconds, including shell overhead and preparation and conclusion commands. To set an exact
+number of runs, you can use the `-r`/`--runs` option:
 ```sh
 hyperfine --runs 5 'sleep 0.3'
 ```
@@ -212,6 +213,13 @@ cave resolve -x repository/rust
 cave resolve -x hyperfine
 ```
 
+### On Funtoo Linux
+
+On Funtoo Linux, hyperfine can be installed [from core-kit](https://github.com/funtoo/core-kit/tree/1.4-release/app-benchmarks/hyperfine):
+```
+emerge app-benchmarks/hyperfine
+```
+
 ### On NixOS
 
 On NixOS, hyperfine can be installed [from the official repositories](https://nixos.org/nixos/packages.html?query=hyperfine):