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scala - Simple play/scala benchmark, rendering a view versus a raw text output comparison

问题描述

I was just benchmarking a new play/scala application.

When performing a simple text output in my action, I get 60K requests per second.

If I render a view (see below), it drops to 13K per second. Since views are just functions in scala, I would have expected that the extra overhead of calling a function wouldn't drop the requests per second down so dramatically.

I only ran the benchmark for 10-30 seconds, would it take longer for the jvm to optimize maybe or this is just expected behavour?

def index() = Action { implicit request: Request[AnyContent] =>
    Ok("hello")
}

If I actually render a view, the requests per second drops to about 13K.

def index() = Action { implicit request: Request[AnyContent] =>
    Ok(views.html.index())
}

/app/views/index.scala.html

@()

@main("Welcome to Play") {
  <h1>Welcome to Play!</h1>
}

/app/views/main.scala.html

@*
 * This template is called from the `index` template. This template
 * handles the rendering of the page header and body tags. It takes
 * two arguments, a `String` for the title of the page and an `Html`
 * object to insert into the body of the page.
 *@
@(title: String)(content: Html)

<!DOCTYPE html>
<html lang="en">
    <head>
        @* Here's where we render the page title `String`. *@
        <title>@title</title>
        <link rel="stylesheet" media="screen" href="@routes.Assets.versioned("stylesheets/main.css")">
        <link rel="shortcut icon" type="image/png" href="@routes.Assets.versioned("images/favicon.png")">

    </head>
    <body>
        @* And here's where we render the `Html` object containing
         * the page content. *@
        @content

      <script src="@routes.Assets.versioned("javascripts/main.js")" type="text/javascript"></script>
    </body>
</html>

标签： scalaplayframework

解决方案

正如我在评论中已经说过的那样，视图不是一个微不足道的功能。它执行字符串连接，并且还调用routes.Assets.versioned了 3 次。分析会话显示，视图基本上只等待这个函数：

在此处输入图像描述

深入研究，我们了解到该versioned函数总是从类路径中重新读取文件：

在此处输入图像描述

也许您可以打开一个问题并询问 Play 框架创建者，是否可以更好地优化资产服务？

编辑：我分析了两个设置。首先我修改了HomeControllerSpec测试：

"render the index page from a new instance of controller" in {
  val controller = new HomeController(stubControllerComponents())
  val indexAction = controller.index()
  val fakeRequest = FakeRequest(GET, "/")

  var i = 100000
  while (i > 0) {
    indexAction.apply(fakeRequest)
    i -= 1
  }

但这并不排除某些组件在生产模式下的行为会有所不同。因此，我运行sbt stage并启动了生成的应用程序，将分析器附加到正在运行的 JVM，并对分析的 JVM 执行了 10000 个请求。结果是一样的。

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