Set Actor Pool Size

Hi, Dongsheng,

Setting on pool size could be a little tricky. 
Planning pool size before the implementation is good but it depends on whether we can predict the actual throughput of a business host and the performance of it.
As for my own experience, the more effective way to use pool size is to use it as a performance tuning approach.
Say, we deploy a business host online and perform test run for several rounds with actual or estimated loads. During the test, we'll need to observe the queue. For example, if a queue is increasing much faster than the others, it usually means the underlining business host is a performance bottleneck and we'll need to either optimize the business host or simply increase it's pool size as long as there are spare CPU cores to be used. 

Before a project goes live we usually try it out for a period of time, during which we gradually determine the pool size of each business host to achieve the required performance.

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pool size的设置并不会对每一个应用都一样。
在实施之前规划好池大小是好的，但这要看我们是否能预测business host的吞吐量和它的性能。
就我自己的经验而言，将pool size作为一种性能调整的方法比较有用。
比如说，我们在线部署一个business host，在实际或预估负载的情况下，进行几轮测试运行。在测试过程中，我们需要观察队列的情况。例如，如果一个队列的增长速度比其他队列快得多，通常意味着对应的business host是一个性能瓶颈，我们需要对它进行优化，或者，只要有空余的CPU核心可以使用，增加它的pool size通常就会带来可观的性能提升。

在项目上线之前我们通常会试运行一段时间，期间逐步确定每一个business host的pool size以达到所需的性能。