哪个更快：MRI Ruby或JRuby？

Question

If I am using Ruby on Rails, should I install MRI/YARV Ruby or JRuby? Which is faster?

Answer 1

Recent benchmarks put JRuby in the lead, followed by MagLev, Rubinius, then MRI.

Benchmarking is tricky. The Ruby Benchmark Suite is what most use to benchmark Ruby. If you remove any benchmarks that fail across any implementation, you get the following graph.

Notice I used the geometric mean. This is a better indicator of average performance as it normalizes outliers and machine specs.

The best benchmark you can run will be specific to your app. If you are looking for overall performance, you'll likely want to use real threads, so Rubinius or JRuby are your only real choices.

Also, each implementation is fast at different things. MRI is very fast at starting up, so it's good for scripts. For longer-running applications (like a web application) Rubinius or JRuby will generally perform better than MRI.

Answer 2

The answer depends on many variables.

But in general, Ruby 1.9 is faster than JRuby, but Ruby 1.8 is slower than JRuby.

eg according to the Computer Language Benchmarks Game :

• Ruby 1.9 vs JRuby
• Ruby 1.8 vs JRuby

Also, if your application is multi-threaded, JRuby may have some advantages over standard Ruby
(aka MRI)], depending on how many cores you have.

Answer 3

Actually the answer above is not correct except mikel's answer ,if you observed any benchmark for JVM you'll find it's slow so imagine JRuby's performance compared to CRuby.

Personally I'm an MRI Ruby contributor and I think that the benchmark chart above is not true at all since the introduction of the YARV VM of MRI Ruby , this version became the fastest outthere and lots of benchmarks proved so "See Pat Shaughnessy's benchmarking and comments about the three famous Ruby interpreters MRI Ruby , JRuby and Rubinius". So in my opinion there is no point of comparison due to the following logical points:-

1- C is much faster than Java because it operates directly on Hardware and produces machine code. While JVM produces Bytecode which is considered intermediate code.

2- JRuby contains an additional interpretation step unlike MRI Ruby " Tokenization , Parsing , AST Parsing and generating YARV instructions "Code generation" and finally Code execution" While JRuby contains an additional stage.

3- Garbage collection in MRI Ruby is a lot faster than garbage collection in JRuby even it got better when they introduced some changes in the mark and sweep garbage collection technique.

4- If you surfed most of the companies and technologies used they always used MRI Ruby particularly ruby 1.9 , I rarely saw a company using JRuby or even saw lots of extensions or contributions to it unlike MRI Ruby.

Finally Ruby 1.8 yes it's slower because they were executing code on the AST itself so they used to parse the AST multiple times in order to execute the code.

If I'm wrong at anything I hope anyone corrects me.

Install MRI Ruby dude using RVM or from source. You'll find lots of gems and extensions to work with

Answer 4

Many users answered already in regards to the benchmarks. Your question is specifically for the usage with Rails.

I find it unusual as I don't see clearly the goal of the question. There are many out there using MRI and many using JRuby and many others. I'd go for stability and security and maintainability in that respect, not speed.

However, there is an important difference between MRI and JRuby.

MRI uses a GIL. This means, although you can have multiple threads, only one thread can be active at a time. Also implementation of threads can differ in different Ruby versions. Newer versions use OS threads (good step forward), older versions use green threads instead.

There is no real parallelism in MRI.

MRI is multi-threaded, not thread safe and not parallel.

JRuby is multi-threaded, not thread safe and parallel.

Parallelism can make a difference in speed. Both are not thread safe, so you will have to take care of that anyway. If you look for speed and can exploit parallelism, then I would give JRuby a definite Yes.

Again, I am not sure if speed is the most important factor when deciding between MRI and JRuby. It is the ecosystem. Since you asked for speed I won't get into this any further.

Answer 5

Honestly, it depends on your code. Install RVM or Pik on your machine, install a bunch of different versions of ruby, and try running your code in them.

For example: An application that frequently restarts is not a great candidate for JRuby since JRuby has some ramp-up time before Hotspot is able to effectively optimize your code. Likewise, an application that relies on threads is not a great candidate for Ruby 1.8.7 since Ruby 1.8.X cannot utilize more than 1 core on your processor and thus cannot execute on more than one thread at a time.

Answer 6

There's a really great article done by the guys over at programmingzen.com that compares a lot of the different flavours of ruby. Was published in July last year so still reasonably recent ;) There page compares these:

* Ruby 1.8.7 p299
* Ruby 1.9.1 p378
* Ruby 1.9.2 RC2
* IronRuby 1.0 (Mono 2.4.4)
* JRuby 1.5.1 (Java HotSpot(TM) 64-Bit Server VM 1.6.0_20)
* MagLev (rev 23832)
* Ruby Enterprise Edition 2010.02
* Rubinius 1.0.1

Might be able to find what you're looking for there

http://programmingzen.com/2010/07/19/the-great-ruby-shootout-july-2010/