减小火焰图大小
尽管火焰图主要是通过可视化堆栈顶部的指标来突出显示瓶颈，但它们也可用于了解应用程序的复杂性。
While Flamegraph's highlight bottlenecks primarily through visualizing the top-of-stack metric, they can also be used to understand application complexity.
如果火焰图有很多高涨堆栈，也可以认为是分布式瓶颈。如果我们可以找到减少堆栈大小的方法，比如通过删除不必要的层，这也可以提高应用程序性能。
If a flamegraph has a lot of high rising stacks, this can also be thought of as a distributed bottleneck. If we can find ways to reduce the graph size, perhaps by removing unnecessary layers, this can also improve application performance.
一个简单的优化方式就是替换我们使用的库，这些替代库在主逻辑中（the hottest paths）创建和调用更少的函数。
One potentially low hanging fruit can be replacing libraries with simpler or smarter alternatives that create and call less functions in the hottest paths.
再看看我们通过 2-server-with-optimized-function.js 生成的火焰图。
Let's take a look at the flamegraph we already generated for 2-server-with-optimized-function.js:
在 3-server-with-reduced-call-graph.js 中，我们把 Express 切换为 Fastify。
In 3-server-with-reduced-call-graph.js we change the web framework from Express to Fastify.
我们再生成 3-server-with-reduced-call-graph.js 的火焰图：
Let's generate a flamegraph for 3-server-with-reduced-call-graph.js:
clinic flame --on-port 'autocannon localhost:$PORT' -- node 3-server-with-reduced-call-graph.js
我们来看结果：
Let's take a look at the resulting flamegraph:
这显然更简单，并且更少的蓝色意味着更少执行 node_modules 中的代码。右侧有一个高大的蓝色柱子，但它非常细，说明虽然它存在复杂性，但速度很快。但是，在 handleRequest 仍存在一些热函数，所以我们还可以做更多的优化。
This is clearly simpler, and there's much less blue meaning less activity in dependencies. There's a tall blue column on the right, but it's very thin: therefore there is complexity there, but it is fast. There are, however, some hot frames under handleRequest, so there may still be more we can do.
首先，我们必须确定性能确实已经有所改善。减少函数调用和复杂性并不总能使应用变快。我们可以使用 autocannon 对比 2-server-with-optimized-function.js 和 3-server-with-reduced-call-graph.js 的区别：
First, however, we must confirm that performance really has improved. Reducing function calls and complexity doesn't always result in a faster application. We can measure the difference between 2-server-with-optimized-function.js and 3-server-with-reduced-call-graph.js using autocannon:
可以看到性能有巨大的提升。通过替换到专注于降低函数火焰图复杂性的框架，性能得到了显着改善。事实上，我们现在可以处理接近两倍的请求。
That's a huge improvement. By swapping to a framework that focuses on reducing the function graph complexity, performance has significantly improved. In fact, we can now serve close to double the amount of requests.