default to num logical cpus rather than 4 threads

Cargo.toml

@@ -29,6 +29,7 @@ crossbeam = "0.8.2"
 filesize = "0.2.0"
 ignore = "0.4.2"
 lscolors = { version = "0.13.0", features = ["ansi_term"] }
+num_cpus = "1.15.0"
 once_cell = "1.17.0"
 
 [dev-dependencies]

README.md

@@ -51,6 +51,9 @@ A modern, vibrant, and multi-threaded file-tree visualizer and disk usage analyz
 If the chosen defaults don't meet your requirements and you don't want to bloat your shell configs with aliases, you can use a [configuration file](#configuration-file) instead.
 
 ## Usage
+
+**Note**: The amount of threads used by default is dependent upon how many logical CPUs available in your system.
+
 ```
 erdtree (et) is a multi-threaded filetree visualizer and disk usage analyzer.
 
@@ -75,7 +78,7 @@ Options:
   -s, --sort <SORT>              Sort-order to display directory content [possible values: name, size, size-rev]
       --dirs-first               Always sorts directories above files
   -S, --follow-links             Traverse symlink directories and consider their disk usage; disabled by default
-  -t, --threads <THREADS>        Number of threads to use [default: 4]
+  -t, --threads <THREADS>        Number of threads to use [default: 10]
       --suppress-size            Omit disk usage from output; disabled by default
       --size-left                Show the size on the left, decimal aligned
       --no-config                Don't read configuration file

src/render/context/mod.rs

@@ -92,8 +92,8 @@ pub struct Context {
     #[arg(short = 'S', long)]
     pub follow_links: bool,
 
-    /// Number of threads to use
-    #[arg(short, long, default_value_t = 4)]
+    /// Number of threads to use; defaults to number of logical cores available
+    #[arg(short, long, default_value_t = num_cpus::get())]
     pub threads: usize,
 
     /// Omit disk usage from output; disabled by default