Benchmarks and improve performance of ServletIo#requestBody

benchmarks/src/main/scala/org/http4s/servlet/ServletIoBenchmarks.scala

@@ -0,0 +1,171 @@
+package org.http4s.servlet
+
+import cats.effect.IO
+import cats.effect.std.Dispatcher
+import cats.effect.unsafe.implicits.global
+
+import org.openjdk.jmh.annotations._
+import org.http4s.servlet.NonBlockingServletIo
+
+import java.io.ByteArrayInputStream
+import java.util.concurrent.TimeUnit
+import javax.servlet.{ServletInputStream, ReadListener}
+import javax.servlet.http.HttpServletRequest
+import scala.util.Random
+
+/** To do comparative benchmarks between versions:
+  *
+  * benchmarks/run-benchmark AsyncBenchmark
+  *
+  * This will generate results in `benchmarks/results`.
+  *
+  * Or to run the benchmark from within sbt:
+  *
+  * Jmh / run -i 10 -wi 10 -f 2 -t 1 cats.effect.benchmarks.AsyncBenchmark
+  *
+  * Which means "10 iterations", "10 warm-up iterations", "2 forks", "1 thread". Please note that
+  * benchmarks should be usually executed at least in 10 iterations (as a rule of thumb), but
+  * more is better.
+  */
+@State(Scope.Thread)
+@BenchmarkMode(Array(Mode.Throughput))
+@OutputTimeUnit(TimeUnit.SECONDS)
+class ServletIoBenchmarks {
+
+  @Param(Array("100000"))
+  var size: Int = _
+
+  @Param(Array("1000"))
+  var iters: Int = _
+
+  def servletRequest: HttpServletRequest = new HttpServletRequestStub(
+    new TestServletInputStream(Random.nextBytes(size))
+  )
+
+  @Benchmark
+  def reader() = {
+    val req = servletRequest
+    val servletIo = NonBlockingServletIo[IO](4096)
+
+    def loop(i: Int): IO[Unit] =
+      if (i == iters) IO.unit else servletIo.reader(req).compile.drain >> loop(i + 1)
+
+    loop(0).unsafeRunSync()
+  }
+
+  @Benchmark
+  def requestBody() = {
+    val req = servletRequest
+    val servletIo = NonBlockingServletIo[IO](4096)
+
+    Dispatcher
+      .sequential[IO]
+      .use { disp =>
+        def loop(i: Int): IO[Unit] =
+          if (i == iters) IO.unit else servletIo.requestBody(req, disp).compile.drain >> loop(i + 1)
+
+        loop(0)
+      }
+      .unsafeRunSync()
+  }
+
+  class TestServletInputStream(body: Array[Byte]) extends ServletInputStream {
+    private var readListener: ReadListener = null
+    private val in = new ByteArrayInputStream(body)
+
+    override def isReady: Boolean = true
+
+    override def isFinished: Boolean = in.available() == 0
+
+    override def setReadListener(readListener: ReadListener): Unit = {
+      this.readListener = readListener
+      readListener.onDataAvailable()
+    }
+
+    override def read(): Int = {
+      val result = in.read()
+      if (in.available() == 0)
+        readListener.onAllDataRead()
+      result
+    }
+  }
+
+  case class HttpServletRequestStub(
+      inputStream: ServletInputStream
+  ) extends HttpServletRequest {
+    def getInputStream(): ServletInputStream = inputStream
+
+    def authenticate(x$1: javax.servlet.http.HttpServletResponse): Boolean = ???
+    def changeSessionId(): String = ???
+    def getAuthType(): String = ???
+    def getContextPath(): String = ???
+    def getCookies(): Array[javax.servlet.http.Cookie] = ???
+    def getDateHeader(x$1: String): Long = ???
+    def getHeader(x$1: String): String = ???
+    def getHeaderNames(): java.util.Enumeration[String] = ???
+    def getHeaders(x$1: String): java.util.Enumeration[String] = ???
+    def getIntHeader(x$1: String): Int = ???
+    def getMethod(): String = ???
+    def getPart(x$1: String): javax.servlet.http.Part = ???
+    def getParts(): java.util.Collection[javax.servlet.http.Part] = ???
+    def getPathInfo(): String = ???
+    def getPathTranslated(): String = ???
+    def getQueryString(): String = ???
+    def getRemoteUser(): String = ???
+    def getRequestURI(): String = ???
+    def getRequestURL(): StringBuffer = ???
+    def getRequestedSessionId(): String = ???
+    def getServletPath(): String = ???
+    def getSession(): javax.servlet.http.HttpSession = ???
+    def getSession(x$1: Boolean): javax.servlet.http.HttpSession = ???
+    def getUserPrincipal(): java.security.Principal = ???
+    def isRequestedSessionIdFromCookie(): Boolean = ???
+    def isRequestedSessionIdFromURL(): Boolean = ???
+    def isRequestedSessionIdFromUrl(): Boolean = ???
+    def isRequestedSessionIdValid(): Boolean = ???
+    def isUserInRole(x$1: String): Boolean = ???
+    def login(x$1: String, x$2: String): Unit = ???
+    def logout(): Unit = ???
+    def upgrade[T <: javax.servlet.http.HttpUpgradeHandler](x$1: Class[T]): T = ???
+    def getAsyncContext(): javax.servlet.AsyncContext = ???
+    def getAttribute(x$1: String): Object = ???
+    def getAttributeNames(): java.util.Enumeration[String] = ???
+    def getCharacterEncoding(): String = ???
+    def getContentLength(): Int = ???
+    def getContentLengthLong(): Long = ???
+    def getContentType(): String = ???
+    def getDispatcherType(): javax.servlet.DispatcherType = ???
+    def getLocalAddr(): String = ???
+    def getLocalName(): String = ???
+    def getLocalPort(): Int = ???
+    def getLocale(): java.util.Locale = ???
+    def getLocales(): java.util.Enumeration[java.util.Locale] = ???
+    def getParameter(x$1: String): String = ???
+    def getParameterMap(): java.util.Map[String, Array[String]] = ???
+    def getParameterNames(): java.util.Enumeration[String] = ???
+    def getParameterValues(x$1: String): Array[String] = ???
+    def getProtocol(): String = ???
+    def getReader(): java.io.BufferedReader = ???
+    def getRealPath(x$1: String): String = ???
+    def getRemoteAddr(): String = ???
+    def getRemoteHost(): String = ???
+    def getRemotePort(): Int = ???
+    def getRequestDispatcher(x$1: String): javax.servlet.RequestDispatcher = ???
+    def getScheme(): String = ???
+    def getServerName(): String = ???
+    def getServerPort(): Int = ???
+    def getServletContext(): javax.servlet.ServletContext = ???
+    def isAsyncStarted(): Boolean = ???
+    def isAsyncSupported(): Boolean = ???
+    def isSecure(): Boolean = ???
+    def removeAttribute(x$1: String): Unit = ???
+    def setAttribute(x$1: String, x$2: Object): Unit = ???
+    def setCharacterEncoding(x$1: String): Unit = ???
+    def startAsync(
+        x$1: javax.servlet.ServletRequest,
+        x$2: javax.servlet.ServletResponse,
+    ): javax.servlet.AsyncContext = ???
+    def startAsync(): javax.servlet.AsyncContext = ???
+  }
+
+}

build.sbt

@@ -43,6 +43,7 @@ lazy val servlet = project
       "org.eclipse.jetty" % "jetty-servlet" % jettyVersion % Test,
       "org.http4s" %% "http4s-dsl" % http4sVersion % Test,
       "org.http4s" %% "http4s-server" % http4sVersion,
+      "org.typelevel" %% "cats-effect" % "3.4.5",
       "org.typelevel" %% "munit-cats-effect-3" % munitCatsEffectVersion % Test,
     ),
   )
@@ -64,3 +65,16 @@ lazy val examples = project
   .dependsOn(servlet)
 
 lazy val docs = project.in(file("site")).enablePlugins(TypelevelSitePlugin)
+
+lazy val benchmarks = project
+  .in(file("benchmarks"))
+  .dependsOn(servlet)
+  .settings(
+    name := "servlet-benchmarks",
+    libraryDependencies ++= Seq(
+      "javax.servlet" % "javax.servlet-api" % servletApiVersion,
+    ),
+    javaOptions ++= Seq(
+      "-Dcats.effect.tracing.mode=none",
+      "-Dcats.effect.tracing.exceptions.enhanced=false"))
+  .enablePlugins(NoPublishPlugin, JmhPlugin)

project/plugins.sbt

@@ -1,2 +1,3 @@
 addSbtPlugin("com.earldouglas" % "xsbt-web-plugin" % "4.2.4")
 addSbtPlugin("org.http4s" % "sbt-http4s-org" % "0.14.9")
+addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.3")

servlet/src/main/scala/org/http4s/servlet/ServletIo.scala

@@ -213,14 +213,11 @@ final case class NonBlockingServletIo[F[_]: Async](chunkSize: Int) extends Servl
       servletRequest: HttpServletRequest,
       dispatcher: Dispatcher[F],
   ): Stream[F, Byte] = {
-    sealed trait Read
-    final case class Bytes(chunk: Chunk[Byte]) extends Read
-    case object End extends Read
-    final case class Error(t: Throwable) extends Read
+    case object End
 
     Stream.eval(F.delay(servletRequest.getInputStream)).flatMap { in =>
-      Stream.eval(Queue.bounded[F, Read](4)).flatMap { q =>
-        val readBody = Stream.exec(F.delay(in.setReadListener(new ReadListener {
+      Stream.eval(Queue.bounded[F, Any](4)).flatMap { q =>
+        val readBody = Stream.eval(F.delay(in.setReadListener(new ReadListener {
           var buf: Array[Byte] = _
           unsafeReplaceBuffer()
 
@@ -238,10 +235,11 @@ final case class NonBlockingServletIo[F[_]: Async](chunkSize: Int) extends Servl
               F.delay(in.read(buf)).flatMap {
                 case len if len == chunkSize =>
                   // We used the whole buffer.  Replace it new before next read.
-                  q.offer(Bytes(Chunk.array(buf))) >> F.delay(unsafeReplaceBuffer()) >> loopIfReady
-                case len if len >= 0 =>
+                  q.offer(Chunk.array(buf)) >> F.delay(unsafeReplaceBuffer()) >> loopIfReady
+                case len if len > 0 =>
                   // Got a partial chunk.  Copy it, and reuse the current buffer.
-                  q.offer(Bytes(Chunk.array(Arrays.copyOf(buf, len)))) >> loopIfReady
+                  q.offer(Chunk.array(Arrays.copyOf(buf, len))) >> loopIfReady
+                case len if len == 0 => loopIfReady
                 case _ =>
                   F.unit
               }
@@ -253,7 +251,7 @@ final case class NonBlockingServletIo[F[_]: Async](chunkSize: Int) extends Servl
             unsafeRunAndForget(q.offer(End))
 
           def onError(t: Throwable): Unit =
-            unsafeRunAndForget(q.offer(Error(t)))
+            unsafeRunAndForget(q.offer(t))
 
           def unsafeRunAndForget[A](fa: F[A]): Unit =
             dispatcher.unsafeRunAndForget(
@@ -263,12 +261,12 @@ final case class NonBlockingServletIo[F[_]: Async](chunkSize: Int) extends Servl
 
         def pullBody: Pull[F, Byte, Unit] =
           Pull.eval(q.take).flatMap {
-            case Bytes(chunk) => Pull.output(chunk) >> pullBody
+            case chunk: Chunk[Byte] @ unchecked => Pull.output(chunk) >> pullBody
             case End => Pull.done
-            case Error(t) => Pull.raiseError[F](t)
+            case t: Throwable => Pull.raiseError[F](t)
           }
 
-        pullBody.stream.concurrently(readBody)
+        readBody.flatMap(_ => pullBody.stream)
       }
     }
   }