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Using TruffleRuby with the SVM

The Substrate Virtual Machine, or SVM, is a closed- and whole-world analysis ahead-of-time compiler for Java, and an implementation of parts of a JVM.

Using the SVM it is possible to ahead-of-time compile TruffleRuby and the Graal dynamic compiler to a single, statically linked native binary executable, that has no dependency on a JVM, and does not link to any JVM libraries. The technique is more sophisticated than just appending a JAR as a resource in a copy of the JVM - only parts of the JVM which are needed are included and they are specialised for how TruffleRuby uses them. There is no Java bytecode - only compiled native machine code and compiler graphs for dynamic compilation.

Note that a common confusion is that the SVM is an ahead-of-time compiler for the Java code that implements the TruffleRuby interpreter and the Graal compiler, not an ahead-of-time compiler for your Ruby program.

The SVM itself, like Graal and TruffleRuby, is implemented in Java.

https://youtu.be/FJY96_6Y3a4?t=10023

To use the SVM you need a release of GraalVM, as described in Using GraalVM. You will also need gcc and the zlib headers. On Ubuntu, Debian, etc:

apt-get install gcc zlib1g-dev

You can then run:

$ graalvm/bin/native-image --ruby

This command will take a few minutes to run, and it requires about 6 GB of memory so don't run it in an instance or machine with less than 8 GB of RAM.

This gives you a native binary that implements Ruby, similar to the MRI or Rubinius executables. This binary is subject to the same OTN licence as the GraalVM distribution.

The binary doesn't need a JVM:

$ otool -L ruby 
ruby:
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1348.28.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.0.0)
	/usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.8)

$ du -h ruby 
144M	ruby

You should set -Xhome= when running an SVM build of TruffleRuby - it can't yet work out where the standard library is located otherwise.

The SVM version of TruffleRuby has better startup performance and lower memory footprint than TruffleRuby or JRuby on the JVM, and better startup performance than Rubinius. We expect these numbers to improve significantly in the future as we ahead-of-time compile more of the Ruby startup process, and aim to meet or beat MRI's startup time.

Implementation Real Time (s) Max RSS (MB)
TruffleRuby SVM 0.40 139
TruffleRuby JVM 5.03 442
JRuby 9.1.7.0 2.25 191
MRI 2.4.0 0.03 8
Rubinius 3.60 0.61 64 
$ /usr/bin/time -l ./ruby -Xhome=jre/languages/ruby -e "puts 'hello'"  # TruffleRuby on the SVM
hello
        0.40 real         0.16 user         0.07 sys
 145813504  maximum resident set size
 
$ /usr/bin/time -l graalvm-0.nn/bin/ruby -e "puts 'hello'"  # TruffleRuby on the JVM
hello
        5.03 real        10.84 user         1.85 sys
 463806464  maximum resident set size
 
$ /usr/bin/time -l jruby-9.1.7.0/bin/jruby -e "puts 'hello'"
hello
       2.25 real         5.27 user         0.30 sys
200794112  maximum resident set size
 
$ /usr/bin/time -l 2.4.0/bin/ruby -e "puts 'hello'"
hello
        0.03 real         0.02 user         0.00 sys
   8773632  maximum resident set size

$ /usr/bin/time -l rbx-3.60/bin/ruby -e "puts 'hello'"
hello
       0.61 real         0.32 user         0.20 sys
  66744320  maximum resident set size

(real is the number of actual seconds which have elapsed while the command runs, resident set size is the total memory occupied while the command runs)