explanation of http benchmark + resources

Author: igrigorik

README.md

@@ -29,3 +29,20 @@ ab -c 5 -n 10 http://127.0.0.1:3000/widgets/http
         Concurrency Level:      5
         Time taken for tests:   2.740 seconds
         Complete requests:      10
+
+Scenario:
+
+ * AB opens 5 concurrent requests (10 total)
+ * Each request to /widgets/http opens an async HTTP request to /widgets - aka, we ourselves spawn another 5 requests
+ * Because the fiber pool is set to 10, it means we can process all 5 requests within ~1s (each mysql req takes 1s)
+ * 10 requests finish in ~2s
+
+So, keep in mind that the size of 'database pool' is basically your concurrency throttle. In example above, we spawn
+10 requests, which open another 10 internally, so in total we process 20 req's in ~2s on a single thing server. Just as expected.
+
+Resources:
+
+ * http://www.slideshare.net/igrigorik/no-callbacks-no-threads-railsconf-2010
+ * http://www.igvita.com/2010/06/07/rails-performance-needs-an-overhaul/
+ * http://www.igvita.com/2010/04/15/non-blocking-activerecord-rails/
+ * http://www.igvita.com/2010/03/22/untangling-evented-code-with-ruby-fibers/