.net事件的性能影响 [英] Performance implications of .net Events

问题描述

我们正在办公室讨论如何解决一个特定的问题，并提出一个事件（不是双关语）。这个回应是否定的滥用，而且它们可能是昂贵的。

我明白了滥用的担忧，我知道他们只是一个特殊的多播代理，最多有一个监听者为什么在方法调用中使用事件被认为是昂贵的？

更新：

只是要清楚这不是关于任何特定的实现，这是一个更通用的问题，关于在方法调用中使用事件的成本。

解决方案

在你的场景中测试 - 我会想到很多很多因素都会影响到这一点，特别是当我们用一种如此低的相对成本来说话时，调用

一个快速简单的测试，发布版本不在调试器下，根据4.0编译为任何cpu，并在64位Windows 7上运行： / p>

另一个编辑：糟糕这是一个更好的结果。请参阅代码，了解它的工作原理。

  10000000直接引用电话：0.011 s 
通过界面拨打10000000电话：0.037 s 
 10000000事件调用：0.067 s 
通过Action< int> ：0.035 s 
  

一个事件增加了一个直接的做无事测试，一千万次通话。 474秒[编辑，只有.026现在在一个更好的机器，但仍然大约是双倍]

我除了您希望在短时间内做这么多电话（在这种情况下可能还有更根本的设计问题），您将更加关心设计的正确性，而不是每1000万次通话的半秒钟。

We were having a discussion at the office on how to solve a particular problem and using an event was raised (no pun intended). The response was negative citing misuse and that they can be expensive.

I understand the concerns behind misuse and I know that they are just a special multicast delegate but given a scenario where there is at most one listener why would using an event over a method call be considered "expensive"?

Update:

Just to be clear this is not about any particular implementation this is a more general question about the cost of using an event over a method call.

解决方案

Test it in your scenario - I would imagine that many, many factors can affect this, especially when we're talking something with such a low relative cost as a method/delegate call.

A quick and simple test with a release build not under a debugger, compiled under 4.0 as "any cpu", and running on 64-bit windows 7:

Another Edit: Oops Here's a better result. See the code for how it's working

10000000 direct reference calls     :   0.011 s
10000000 calls through an interface :   0.037 s
10000000 invocations of an event    :   0.067 s
10000000 calls through Action<int>  :   0.035 s

So in a straight "do nothing test" with ten million calls, an event adds .474 sec [edit, only .026 now on a much better machine, still roughly double however]

I would worry more about correctness of design than half a second every 10 million calls, unless you are expecting to do that many calls in short periods of time (in which case perhaps there is a more fundamental design issue).

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