Merge pull request #55 from wesleywiser/readme

Improve the readme

Author: wesleywiser

README.md

@@ -5,4 +5,34 @@ This crate is maintained by the Rust compiler team and in particular by the
 [self-profile working group][wg-self-profile]. It is currently only meant to
 be used within rustc itself, so APIs may change at any moment.
 
+## Tools
+
+### measureme
+
+`measureme` is the core library which contains a fast, efficient framework for recording events and serializing them to a compact binary format. It is integrated into `rustc` via the unstable `-Z self-profile` flag.
+
+[Documentation](https://docs.rs/measureme)
+
+### summarize
+
+`summarize` produces a human readable summary of `measureme` profilng data.
+It contains two main modes:
+
+- `summarize` which groups the profiling events and orders the results by time taken.
+- `diff` which compares two profiles and outputs a summary of the differences.
+
+[Learn more](./summarize/Readme.md)
+
+### stack_collapse
+
+`stack_collapse` reads `measureme` profiling data and outputs folded stack traces compatible with the [Flame Graph](https://github.com/brendangregg/FlameGraph) tools.
+
+[Learn more](./stack_collapse/README.md)
+
+### crox
+
+`crox` turns `measureme` profiling data into files that can be visualized by the Chromium performance tools.
+
+[Learn more](./crox/Readme.md)
+
 [wg-self-profile]: https://rust-lang.github.io/compiler-team/working-groups/self-profile/