doc: add more info to benchmark/README.md

Fishrock123 · Fishrock123 · commit 514b1d964b2e · 2015-01-28T16:56:26.000-05:00
Adds info on the `wrk` prerequisite for http benchmarks and how to run benchmarks with options. PR-URL: nodejs#629 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: Evan Lucas <evanlucas@me.com>
diff --git a/benchmark/README.md b/benchmark/README.md
@@ -3,6 +3,14 @@
 This folder contains benchmark tests to measure the performance for certain
 io.js APIs.
 
+## prerequisites
+
+Most of the http benchmarks require `wrk` to be compiled beforehand.
+
+```sh
+make wrk
+```
+
 ## How to run tests
 
 There are two ways to run benchmark tests:
@@ -80,6 +88,20 @@ buffers/buffer-read.js noAssert=false buffer=fast type=UInt16BE millions=1: 245.
 ...
 ```
 
+3. Run tests with options
+
+This example will run only the first type of url test, with one iteration.
+(Note: benchmarks require __many__ iterations to be statistically accurate.)
+
+
+```sh
+iojs benchmark/url/url-parse.js type=one n=1
+```
+Output:
+```
+url/url-parse.js type=one n=1: 1663.74402
+```
+
 ## How to write a benchmark test
 
 The benchmark tests are grouped by types. Each type corresponds to a subdirectory,
