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import java.io.PrintWriter
import java.io.FileOutputStream
import java.util.Calendar
import scala.tools.nsc.interactive.tests._
import scala.tools.nsc.util._
import scala.tools.nsc.io._
import scala.tools.nsc.doc
/** This test runs the presentation compiler on the Scala compiler project itself and records memory consumption.
*
* The test scenario is to open Typers, Trees and Types, then repeatedly add and remove one character
* in Typers.scala. Each step causes the parser, namer, and type checker to run.
*
* At each step we record the memory usage after the GC has run. At the end of the test,
* simple linear regression is used to compute the straight line that best fits the
* curve, and if the slope is higher than 1 (meaning a leak of 1MB/run), we fail the test.
*
* The Scala compiler sources are assumed to be under 'basedir/src/compiler'.
*
* The individual data points are saved under 'usedMem-<date>.txt', under the test project
* directory. Use the cool graph-it.R (https://github.com/scala-ide/scala-ide/blob/master/org.scala-ide.sdt.core.tests/graph-it.R)
* script to see the memory curve for the given test run.
*/
object Test extends InteractiveTest {
final val mega = 1024 * 1024
override val withDocComments = true
override def execute(): Unit = memoryConsumptionTest()
def batchSource(name: String) =
new BatchSourceFile(AbstractFile.getFile(name))
def memoryConsumptionTest() {
val N = 50
val filename = "usedmem-%tF.txt".format(Calendar.getInstance.getTime)
val typerUnit = AbstractFile.getFile(baseDir.parent.parent.parent.parent / "src/compiler/scala/tools/nsc/typechecker/Typers.scala")
val typesUnit = AbstractFile.getFile(baseDir.parent.parent.parent.parent / "src/reflect/scala/reflect/internal/Types.scala")
val treesUnit = AbstractFile.getFile(baseDir.parent.parent.parent.parent / "src/reflect/scala/reflect/internal/Trees.scala")
askReload(Seq(new BatchSourceFile(typerUnit), new BatchSourceFile(typesUnit), new BatchSourceFile(treesUnit)))
typeCheckWith(treesUnit, new String(treesUnit.toCharArray))
typeCheckWith(typesUnit, new String(typesUnit.toCharArray))
val originalTyper = new String(typerUnit.toCharArray)
val (prefix, postfix) = originalTyper.splitAt(originalTyper.indexOf("import global._"))
val changedTyper = prefix + " a\n " + postfix
val usedMem = for (i <- 1 to N) yield {
val src = if (i % 2 == 0) originalTyper else changedTyper
val usedMem = withGC {
typeCheckWith(typerUnit, src)
}
usedMem / mega // report size in MB
}
//dumpDataToFile(filename, usedMem)
// drop the first two measurements, since the compiler needs some memory when initializing
val (a, b) = linearModel((3L to N).toSeq, usedMem.drop(2))
//println("LinearModel: constant: %.4f\tslope:%.4f".format(a, b))
if (b > 1.0)
println("Rate of memory consumption is alarming! %.4f MB/run".format(b))
else
println("No leaks detected.")
}
private def typeCheckWith(file: AbstractFile, src: String) = {
val sourceFile = new BatchSourceFile(file, src.toCharArray)
askReload(Seq(sourceFile))
askLoadedTyped(sourceFile).get // block until it's here
}
private def dumpDataToFile(filename: String, usedMem: Seq[Long]) {
val outputFile = new PrintWriter(new FileOutputStream(filename))
outputFile.println("\tusedMem")
for ((dataPoint, i) <- usedMem.zipWithIndex) {
outputFile.println("%d\t%d".format(i, dataPoint))
}
outputFile.close()
}
/** Return the linear model of these values, (a, b). First value is the constant factor,
* second value is the slope, i.e. `y = a + bx`
*
* The linear model of a set of points is a straight line that minimizes the square distance
* between the each point and the line.
*
* See: http://en.wikipedia.org/wiki/Simple_linear_regression
*/
def linearModel(xs: Seq[Long], ys: Seq[Long]): (Double, Double) = {
require(xs.length == ys.length)
def mean(v: Seq[Long]): Double = v.sum.toDouble / v.length
val meanXs = mean(xs)
val meanYs = mean(ys)
val beta = (mean((xs, ys).zipped.map(_ * _)) - meanXs * meanYs) / (mean(xs.map(x => x * x)) - meanXs * meanXs)
val alfa = meanYs - beta * meanXs
(alfa, beta)
}
/** Run the given closure and return the amount of used memory at the end of its execution.
*
* Runs the GC before and after the execution of `f'.
*/
def withGC(f: => Unit): Long = {
val r = Runtime.getRuntime
System.gc()
f;
System.gc()
r.totalMemory() - r.freeMemory()
}
}
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