Allocation tracking in Rubinius using dtrace/Systemtap. This is still an experiment and might never actually make it into a release.

alloc.stp

global allocations

probe process("rbx").mark("object__allocate")
{
    klass = user_string($arg1)

    allocations[klass] <<< 1
}

probe end
{
    printf("%-40s %s\n", "Class", "Amount");

    foreach ( [klass] in allocations- )
    {
        printf("%-40s %d\n", klass, @count(allocations[klass]))
    }
}

output.txt

$ sudo -E stap /tmp/alloc.stp -c 'rbx /tmp/test.rb'
WARNING: Kernel function symbol table missing [man warning::symbols]
Class                                    Amount
File::Stat                               7889
Hash::Bucket                             7611
CodeTools::Generator::BasicBlock         5047
Rubinius::Mirror::Array                  2094
CodeTools::Generator::Label              1922
CodeTools::AST::ArrayLiteral             1626
CodeTools::Compiler::LocalReference      1575
Hash::State                              1477
Hash                                     1461
CodeTools::AST::Arguments                1453
CodeTools::AST::LocalVariableAccess      1349
Array                                    1296
CodeTools::AST::Send                     1170
CodeTools::AST::StringLiteral            1080
CodeTools::AST::SendWithArguments        1079
CodeTools::AST::ConstantAccess           933
CodeTools::AST::Self                     858
CodeTools::AST::Block                    758
Rubinius::InstructionSequence            658
CodeTools::AST::State                    658
CodeTools::Generator                     658
CodeTools::Compiler::LocalVariable       634
CodeTools::AST::Parameters               583
CodeTools::AST::NilLiteral               425
CodeTools::AST::SymbolLiteral            362
CodeTools::AST::ScopedConstant           362
CodeTools::AST::If                       327
CodeTools::AST::InstanceVariableAccess   310
CodeTools::AST::LocalVariableAssignment  307
CodeTools::AST::Define                   272
CodeTools::AST::ToString                 266
CodeTools::AST::ElementAssignment        249
CodeTools::AST::InstanceVariableAssignment 230
Rubinius::Mirror::String                 212
CodeTools::AST::DynamicString            172
CodeTools::AST::Iter                     169
String                                   167
CodeTools::AST::DefineSingletonScope     142
CodeTools::AST::DefineSingleton          142
CodeTools::AST::FixnumLiteral            117
Rubinius::InstructionSet::OpCode         105
Rubinius::FFI::DynamicLibrary::Symbol    105
CodeTools::Compiler::NestedLocalReference 92
CodeTools::AST::Return                   81
CodeTools::AST::And                      73
Rubinius::CodeLoader                     73
CodeTools::AST::OpAssignOr               69
CodeTools::AST::SendFastNew              68
CodeTools::AST::RegexLiteral             68
CodeTools::AST::When                     64
Rubinius::LoadedFeatures                 64
Rubinius::ConstantScope                  63
Rubinius::CompiledCode::Script           62
Rubinius::CodeLoader::RequireRequest     62
CodeTools::AST::EmptyArray               57
CodeTools::AST::Class                    46
CodeTools::AST::TrueLiteral              44
CodeTools::AST::ConstantAssignment       43
CodeTools::AST::Begin                    43
CodeTools::AST::FalseLiteral             39
CodeTools::AST::Or                       37
CodeTools::AST::NthRef                   37
Range                                    37
CodeTools::AST::ScopedClassName          33
Enumerable::SortedElement                30
CodeTools::AST::AttributeAssignment      29
CodeTools::AST::Defined                  29
CodeTools::AST::ClassScope               28
CodeTools::AST::ClassVariableAccess      28
CodeTools::Compiler::FileParser          27
CodeTools::Compiler::Bytecode            27
CodeTools::Melbourne                     27
CodeTools::Compiler::Packager            27
CodeTools::AST::Script                   27
CodeTools::Compiler::Writer              27
CodeTools::Compiler::Encoder             27
CodeTools::Compiler                      27
Method                                   27
CodeTools::AST::Alias                    25
Rubinius::Options::Option                25
CodeTools::AST::DefaultArguments         24
CodeTools::AST::HashLiteral              24
UnboundMethod                            21
CodeTools::AST::ClassVariableAssignment  18
CodeTools::AST::EmptyBody                18
CodeTools::AST::RescueCondition          18
CodeTools::AST::MultipleAssignment       17
CodeTools::AST::Module                   17
CodeTools::AST::ModuleScope              17
CodeTools::AST::Rescue                   17
CodeTools::AST::ReceiverCase             16
CodeTools::AST::ModuleName               16
CodeTools::AST::Match3                   15
CodeTools::AST::Next                     15
CodeTools::AST::ZSuper                   13
CodeTools::AST::ClassName                13
CodeTools::AST::Yield                    13
CodeTools::AST::Super                    12
CodeTools::AST::BlockPass19              11
CodeTools::AST::BlockArgument            11
CodeTools::AST::Ensure                   10
CodeTools::AST::SplatValue               10
CodeTools::AST::GlobalVariableAccess     10
CodeTools::AST::ConcatArgs               9
CodeTools::AST::While                    9
Rubinius::LRUCache::Entry                7
Rubinius::IdentityMap                    7
CodeTools::AST::ToplevelConstant         6
CodeTools::AST::CurrentException         5
CodeTools::AST::DynamicRegex             5
Dir::Glob::ConstantEntry                 4
Dir::Glob::Environment                   3
Mutex                                    3
CodeTools::AST::Match2                   3
CodeTools::AST::BlockGiven               3
CodeTools::AST::Range                    3
CodeTools::AST::OpAssignElement          3
Dir::Glob::ConstantDirectory             3
Dir::Glob::RootDirectory                 3
CodeTools::AST::SClass                   3
CodeTools::AST::SClassScope              3
Rubinius::Hook                           3
Object                                   2
Gem::Requirement                         2
Gem::Platform                            2
CodeTools::AST::Until                    2
CodeTools::AST::BackRef                  2
Dir::Glob::RecursiveDirectories          2
Rubinius::FFI::DynamicLibrary            2
CodeTools::Compiler::LRUCache::Entry     2
CodeTools::AST::File                     2
Rubinius::LRUCache                       2
Monitor                                  1
LoadError                                1
Gem::Version                             1
CodeTools::AST::DynamicSymbol            1
Dir::Glob::EntryMatch                    1
Rubinius::Options                        1
CodeTools::AST::OpAssignAttribute        1
Rubinius::Console::Server                1
CodeTools::Compiler::LRUCache            1
Rubinius::EnvironmentVariables           1
Binding                                  1
CodeTools::AST::ScopedModuleName         1
Complex                                  1
Rubinius::FFI::Pointer                   1
Rubinius::Loader                         1
Rubinius::ARGFClass                      1
CodeTools::AST::Break                    1
Rubinius::GlobalVariables                1
Rubinius::Configuration                  1
ThreadGroup                              1

test.rb

name   = 'Foo'
number = 10
list   = []
hash   = {}