CompilerDNA (Jikes RVM API)

java.lang.Object
- org.jikesrvm.adaptive.recompilation.CompilerDNA

```
public class CompilerDNA
extends Object
```
This class codifies the cost/benefit properties of the various compilers used in the adaptive optimization system.
The DNA tells the AOS two important kinds of averages for each optimization level: the cost of compiling at an optimization level (as measured in bytecode/milliseconds) and the expected speedup of the resulting code (relative to the first compiler).
There is an AOS command-line option to set the compiler DNA. The method readDNA(java.lang.String) contains a comment on the expected format.
This DNA was gathered on July 9, 2008 using revision r14679 + the bugfix in r14688. The PowerPC data was gathered on piccolo.watson.ibm.com (JS21, machine type 8884; ppc64-aix). The IA32 data was gathered on lyric.watson.ibm.com (LS41, machine type 7972; x86_64-linux).

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`BASELINE`
`private static double[][]`	`benefitRatio` Benefits of moving from one compilation level to another USAGE NOTE: The data is layed out in a upper triangular matrix
`private static double[]`	`compilationRates` Average bytecodes compiled per millisecond.
`private static String[]`	`compilerNames`
`private static double[][]`	`compileTimeRatio` Compile time ratio of one compilation level to another For example, if compiler1 (say OPT1) compiles at 50 bc/msec and compiler2 (say OPT2) compiles at 100 bc/msec, compileTimeRatio[OPT1][OPT2] = 2 USAGE NOTE: The data is layed out in a upper triangular matrix
`private static int`	`numCompilers` The number of compilers available
`(package private) static int`	`OPT0`
`(package private) static int`	`OPT1`
`(package private) static int`	`OPT2`
`private static double[]`	`speedupRates` What is the execution rate of each compiler normalized to the 1st compiler

Constructor Summary

Constructors
Constructor and Description

CompilerDNA()

Constructors
Constructor and Description
`CompilerDNA()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static double`	`estimateCompileTime(int compiler, NormalMethod meth)` Estimate how long (in milliseconds) it will/did take the given compiler to compile the given method.
`static double`	`getBaselineCompilationRate()` Returns the compilation rates of the baseline compiler in bytecodes/millisecond.
`static double`	`getBenefitRatio(int compiler1, int compiler2)` This method returns the expected speedup from going from compiler1 to compiler2
`static int`	`getCompilerConstant(int optLevel)` maps opt levels to the compiler
`static String`	`getCompilerString(int compiler)` maps a compiler constant to a string
`static double`	`getCompileTimeRatio(int compiler1, int compiler2)` What is the additional overhead (relative to compiler1 compile time) of compile2 compile time.
`static int`	`getNumberOfCompilers()` returns the number of compilers
`static int`	`getOptLevel(int compiler)` A mapping from an Opt compiler number to the corresponding Opt level
`static void`	`init()` initialize static fields
`private static void`	`initializeCompilerRatioArrays()`
`private static void`	`processOneLine(LineNumberReader in, String title, double[] valueHolder)` Helper method to read one line of the DNA file
`private static void`	`readDNA(String filename)` Read a serialized representation of the DNA info

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - compilerNames
```
private static final String[] compilerNames
```
  - BASELINE
```
public static final int BASELINE
```
    See Also:
    
    Constant Field Values
  - OPT0
```
static final int OPT0
```
    See Also:
    
    Constant Field Values
  - OPT1
```
static final int OPT1
```
    See Also:
    
    Constant Field Values
  - OPT2
```
static final int OPT2
```
    See Also:
    
    Constant Field Values
  - numCompilers
```
private static int numCompilers
```
    The number of compilers available
  - compilationRates
```
private static final double[] compilationRates
```
    Average bytecodes compiled per millisecond.
  - speedupRates
```
private static final double[] speedupRates
```
    What is the execution rate of each compiler normalized to the 1st compiler
  - benefitRatio
```
private static double[][] benefitRatio
```
    Benefits of moving from one compilation level to another USAGE NOTE: The data is layed out in a upper triangular matrix
  - compileTimeRatio
```
private static double[][] compileTimeRatio
```
    Compile time ratio of one compilation level to another For example, if compiler1 (say OPT1) compiles at 50 bc/msec and compiler2 (say OPT2) compiles at 100 bc/msec, compileTimeRatio[OPT1][OPT2] = 2 USAGE NOTE: The data is layed out in a upper triangular matrix
- Constructor Detail
  - CompilerDNA
```
public CompilerDNA()
```
- Method Detail
  - getBenefitRatio
```
public static double getBenefitRatio(int compiler1,
                                     int compiler2)
```
    This method returns the expected speedup from going from compiler1 to compiler2
    
    Parameters:
    
    compiler1 - old compiler
    
    compiler2 - new compiler
    
    Returns:
    
    the benefit ratio (speedup) of moving from compiler1 to compiler2
  - getCompileTimeRatio
```
public static double getCompileTimeRatio(int compiler1,
                                         int compiler2)
```
    What is the additional overhead (relative to compiler1 compile time) of compile2 compile time. For example, if compiler1 compiles at 50 bc/msec and compiler2 compiles at 100 bc/msec, this method returns 2
    
    Parameters:
    
    compiler1 - the compiler whose compile time we compare to
    
    compiler2 - the compiler's compile time we care about
    
    Returns:
    
    the additional overhead (relative to compiler1 compile time) of compile2 compile time
  - estimateCompileTime
```
public static double estimateCompileTime(int compiler,
                                         NormalMethod meth)
```
    Estimate how long (in milliseconds) it will/did take the given compiler to compile the given method.
    
    Parameters:
    
    compiler - the compiler to compile meth
    
    meth - the method to be compiled
    
    Returns:
    
    an estimate of compile time (in milliseconds)
  - getBaselineCompilationRate
```
public static double getBaselineCompilationRate()
```
    Returns the compilation rates of the baseline compiler in bytecodes/millisecond.
    
    Returns:
    
    the compilation rates of the baseline compiler in bytecodes/millisecond
  - init
```
public static void init()
```
    initialize static fields
  - initializeCompilerRatioArrays
```
private static void initializeCompilerRatioArrays()
```
  - readDNA
```
private static void readDNA(String filename)
```
    Read a serialized representation of the DNA info
    
    Parameters:
    
    filename - DNA filename
  - processOneLine
```
private static void processOneLine(LineNumberReader in,
                                   String title,
                                   double[] valueHolder)
                            throws IOException
```
    Helper method to read one line of the DNA file
    
    Parameters:
    
    in - the LineNumberReader object
    
    title - the title string to look for
    
    valueHolder - the array to hold the read values
    
    Throws:
    
    IOException - when there's a failure during processing of the file
  - getNumberOfCompilers
```
public static int getNumberOfCompilers()
```
    returns the number of compilers
    
    Returns:
    
    the number of compilers
  - getOptLevel
```
public static int getOptLevel(int compiler)
```
    A mapping from an Opt compiler number to the corresponding Opt level
    
    Parameters:
    
    compiler - the compiler constant of interest
    
    Returns:
    
    the Opt level that corresponds to the Opt compiler constant passed
  - getCompilerString
```
public static String getCompilerString(int compiler)
```
    maps a compiler constant to a string
    
    Parameters:
    
    compiler - the constant for the compiler
    
    Returns:
    
    the string that represents the passed compiler constant
  - getCompilerConstant
```
public static int getCompilerConstant(int optLevel)
```
    maps opt levels to the compiler
    
    Parameters:
    
    optLevel - opt level
    
    Returns:
    
    the opt level that corresponds to the passed compiler constant

Class CompilerDNA

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

compilerNames

BASELINE

OPT0

OPT1

OPT2

numCompilers

compilationRates

speedupRates

benefitRatio

compileTimeRatio

Constructor Detail

CompilerDNA

Method Detail

getBenefitRatio

getCompileTimeRatio

estimateCompileTime

getBaselineCompilationRate

init

initializeCompilerRatioArrays

readDNA

processOneLine

getNumberOfCompilers

getOptLevel

getCompilerString

getCompilerConstant