README.md in alba-3.5.0

- old
+ new

@@ -1,9 +1,27 @@
 ## Benchmark for json serializers
 
-This directory contains a few different benchmark scripts. They all use inline Bundler definitions so you can run them by `ruby benchmark/collection.rb` for instance.
+This directory contains a few different benchmark scripts.
 
+## How to run
+
+```
+bundle install
+
+# with `Oj.optimize_rails`
+bundle exec ruby collection.rb
+
+# without `Oj.optimize_rails`
+NO_OJ_OPTIMIZE_RAILS=1 bundle exec ruby collection.rb
+
+# with `Oj.optimize_rails` and YJIT
+YJIT=1 bundle exec ruby collection.rb
+
+# with YJIT and without `Oj.optimize_rails`
+YJIT=1 NO_OJ_OPTIMIZE_RAILS=1 bundle exec ruby collection.rb
+```
+
 ## Result
 
 As a reference, here's the benchmark result run in my (@okuramasafumi) machine.
 
 Machine spec:
@@ -63,11 +81,11 @@
        representable:       43.4 i/s - 10.55x  slower
           simple_ams:       34.7 i/s - 13.20x  slower
                  ams:       14.2 i/s - 32.28x  slower
 ```
 
-`benchmark-ips` with `Oj.optimize_rail` and YJIT:
+`benchmark-ips` with `Oj.optimize_rails` and YJIT:
 
 ```
 Comparison:
                panko:      676.6 i/s
          jserializer:      285.3 i/s - 2.37x  slower
@@ -80,10 +98,10 @@
        representable:       73.5 i/s - 9.21x  slower
           simple_ams:       62.8 i/s - 10.77x  slower
                  ams:       20.4 i/s - 33.10x  slower
 ```
 
-`benchmark-ips` with YJIT and without `Oj.optimize_rail`:
+`benchmark-ips` with YJIT and without `Oj.optimize_rails`:
 
 ```
 Comparison:
                panko:      701.9 i/s
                 alba:      311.1 i/s - 2.26x  slower