3 files changed, 10 insertions, 3 deletions

diff --git a/Cargo.toml b/Cargo.toml
index b0c1013..e4071cd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ license = "MIT"
 build = "build.rs"
 
 [features]
-default = []
+default = ["performance-counter"]
 performance-counter = ["phf", "phf_codegen", "csv", "serde_json"]
 
 [[test]]
diff --git a/README.md b/README.md
index 48ab566..e19ddc6 100644
--- a/README.md
+++ b/README.md
@@ -16,5 +16,12 @@ Currently supports
 
 This library depends on libcore so it can be used in kernel level code.
 
+## Features
+
+  * performance-counter: Includes the performance counter information. Note this feature
+    can increase compilation time significantly due to large statically generated hash-tables
+    that are included in the source. In case you do not need performance-counter information
+    you can disable it using: `cargo build --no-default-features`
+
 ## Documentation
- * [API Documentation](http://gz.github.io/rust-x86/x86/)
\ No newline at end of file
+ * [API Documentation](http://gz.github.io/rust-x86/x86/)
diff --git a/src/lib.rs b/src/lib.rs
index 7640900..fb823aa 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,4 @@
-#![feature(no_std, core_str_ext, core_slice_ext, const_fn)]
+#![feature(const_fn)]
 #![feature(asm)]
 #![no_std]
 #![cfg_attr(test, allow(unused_features))]