front-end tuning Vs back-end tweaking

Steve Sounders said:"So if what you are really trying to do is deal with scalability issues, the place to focus is the back-end. If you’re having a huge spike in traffic or a large increase in the amount of data or back-end calculations that you need to do, then the place of focus is on the back-end.But if your objective is making user experience faster, the place of focus is the front-end."

从这句话里我得到的信息是如果一个软件的构架做好了，开发做好本职工作，那么性能调优的重点都将放在前端，也就是从HTML产生后的一系列动作。

但往往我们所遇到的问题是先要排除后面一些严重而明显的缺陷，deadlock，memory leak，CPU% high utilization，GC efficiency，caching mechanism，indexing，isolation level setting，临时文件创建以及删除的规则。这些都是跟最初的设计相关，并且影响performance和scalability！在不同的阶段考虑不同的方案，这是我们应该做好计划的。