ZipPy on Truffle

Wei Zhang

University of California, Irvine

is?

  • Python 3 using Truffle

  • 80% language completeness

  • https://bitbucket.org/ssllab/zippy

Trufflization
Generators
Performance

Numeric Types

CPython

ZipPy

Using Truffle DSL

        @Specialization(order = 0)
        int doBoolean(boolean left, boolean right) {
            final int leftInt = left ? 1 : 0;
            final int rightInt = right ? 1 : 0;
            return leftInt + rightInt;
        }

        @Specialization(rewriteOn = ArithmeticException.class, order = 1)
        int doBoolean(int left, boolean right) {
            final int rightInt = right ? 1 : 0;
            return ExactMath.addExact(left, rightInt);
        }

        @Specialization(rewriteOn = ArithmeticException.class, order = 2)
        int doBoolean(boolean left, int right) {
            final int leftInt = left ? 1 : 0;
            return ExactMath.addExact(leftInt, right);
        }

        @Specialization(rewriteOn = ArithmeticException.class, order = 5)
        int doInteger(int left, int right) {
            return ExactMath.addExact(left, right);
        }

        @Specialization(order = 6)
        BigInteger doIntegerBigInteger(int left, BigInteger right) {
            return BigInteger.valueOf(left).add(right);
        }

        @Specialization(order = 7)
        BigInteger doBigIntegerInteger(BigInteger left, int right) {
            return left.add(BigInteger.valueOf(right));
        }

        @Specialization(order = 10)
        BigInteger doBigInteger(BigInteger left, BigInteger right) {
            return left.add(right);
        }

        @Specialization(order = 13)
        double doDoubleBoolean(double left, boolean right) {
            final double rightDouble = right ? 1.0 : 0.0;
            return left + rightDouble;
        }

        @Specialization(order = 14)
        double doDoubleBoolean(boolean left, double right) {
            final double leftDouble = left ? 1.0 : 0.0;
            return leftDouble + right;
        }

        @Specialization(order = 15)
        double doDoubleInt(double left, int right) {
            return left + right;
        }

        @Specialization(order = 16)
        double doDoubleInt(int left, double right) {
            return left + right;
        }

        @Specialization(order = 20)
        double doDouble(double left, double right) {
            return left + right;
        }

Sequence Types

  • range: generate indices

  • list: mutable, likely homogeneous

  • tuple: immutable, heterogeneous

for range loop

    def sum(n):
      ttl = 0
      for i in range(n):
        ttl += i
      return ttl
    @Specialization(order = 1)
    public Object doPRange(VirtualFrame frame, PRangeIterator range) {
        final int start = range.getStart();
        final int stop = range.getStop();
        final int step = range.getStep();
        for (int i = start; i < stop; i += step) {
            ((WriteNode) target).executeWrite(frame, i);
            body.executeVoid(frame);
        }
    
        return PNone.NONE;
    }

for range loop

    def sum(n):
      ttl = 0
      for i in range(n):
        ttl += i
      return ttl
    public int sum(int n) {
        int ttl = 0;
        
        for (int i = 0; i < n; i ++) {
            ttl += i;
        }
    
        return ttl;
    }

for range loop

    def sum(n):
      ttl = 0
      for i in range(n):
        ttl += i
      return ttl
          jmp L7
    
    L6:   mov       ecx, edx
          add       ecx, ebp
          jo        L8
          mov       edx, ebp
          incl      edx
          mov       esi, ebp
          mov       ebp, edx
          mov       edx, ecx
    L7:   cmp       eax, ebp
          jle       L9
          jmp       L6
    L8:   call      deoptimize()
    
    L9:

List Storages


    def makelist(n):
      lst = []
      for i in range(n):
        lst.append(i)
      return lst

List Storages


    def makelist(n):
      lst = []
      for i in range(n):
        lst.append(i)
      return lst

List Storages


    def makelist(n):
      lst = []
      for i in range(n):
        lst.append(i)
      return lst

List Storages


    def makelist(n):
      lst = []
      for i in range(n):
        lst.append(i)
      return lst

Object Model


class Tofu:
  pass

class SpicyTofu(Tofu):
  def __init__(self, c):
    self.c = c

class MapoTofu(SpicyTofu):
  def __init__(self, c, m):
    SpicyTofu.__init__(self,c)
    self.m = m

Object Model


class Tofu:
  pass

class SpicyTofu(Tofu):
  def __init__(self, c):
    self.c = c

class MapoTofu(SpicyTofu):
  def __init__(self, c, m):
    SpicyTofu.__init__(self,c)
    self.m = m
public class FixedPythonObjectStorage 
    extends PythonObject {

    protected Object[] arrayObjects;
    protected int primitiveInt0;
    protected int primitiveInt1;
    protected int primitiveInt2;
    protected int primitiveInt3;
    protected int primitiveInt4;

    protected double primitiveDouble0;
    protected double primitiveDouble1;
    protected double primitiveDouble2;
    protected double primitiveDouble3;
    protected double primitiveDouble4;

    protected Object fieldObject0;
    protected Object fieldObject1;
    protected Object fieldObject2;
    protected Object fieldObject3;
    protected Object fieldObject4;
    ...

Object Model


class Tofu:
  pass

class SpicyTofu(Tofu):
  def __init__(self, c):
    self.c = c

class MapoTofu(SpicyTofu):
  def __init__(self, c, m):
    SpicyTofu.__init__(self,c)
    self.m = m
public class MapoTofuObjectStorage 
    extends PythonObject {

    protected Object[] arrayObjects;
    protected int cInt;
    protected int mInt;

    ...

Generators


  def producer(n):
    for i in range(n):
      yield i

  for i in producer(3):
    print(i)

  # 0, 1, 2

  g = producer(3)
  try:
    while True:
      print(g.__next__())
  except StopIteration:
    pass
  
  # 0, 1, 2

Generator Expressions


  n = 3
  g =(x for x in range(n))
  sum(g)
  # 3

  def _producer():
    for x in range(n):
      yield x
  _producer()

Execution Order

The Problems?

  • suspend and resume prevent frame optimizations

  • the __next__ call is expensive

  • 90% of the top 50 Python projects on PyPI and GitHub use generators

Bytecode Interpreter

  • iterative
  • store control-flow state in bytecode index

AST

Interpreter

  • recursive
  • store control-flow state on the call stack

Generator AST

class WhileNode extends PNode {
  protected ConditionNode condition;
  protected PNode body;

  public Object execute(Frame frame) {
    try {
      while(condition.execute(frame)) {
        body.execute(frame);
      }
    } catch (BreakException e) {
      // break the loop
    }
    return PNone.NONE;
  }
}
class GenWhileNode extends WhileNode {
  private final int flagSlot;

  public Object execute(Frame frame) {
    try {
      while(isActive(frame) ||      
            condition.execute(frame)) {
        setActive(frame, true)
        body.execute(frame);
        setActive(frame, false);
      }
    } catch (BreakException e) {
      setActive(frame, false);
    }
    return PNone.NONE;
  }
}

Generator AST

Generator Peeling

Generator Peeling

Generator Peeling

The End Result

  • caller frame and generator frame can be optimized

  • peeling inlines the __next__ call

  • no generator AST nodes

Benchmarking

  • against CPython, Jython, PyPy

  • measure peak performance

  • generator-bound and traditional benchmarks

Performance of Generator Benchmarks

Performance of Traditional Benchmarks

Lesson Learned

  • Trufflised AST is a good start

  • but there's a lot more...

Thanks!

多谢!

ZipPy on Truffle

By Wei Zhang

ZipPy on Truffle

  • 1,119
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