Profiling is really useful for any moderately complex application, particularly where you have dependencies upon a bunch of third party code. While your code m

Profiling is really useful for any moderately complex application, particularly where you have dependencies upon a bunch of third party code. While your code may look all nice and sane, not have any glaring performance issues - what you may not realise is that you're using a framework that does things in unexpected ways. The devs I work with are running into the reality of this at the moment - they blame the servers/network/database/whatever as being slow/shit/etc. I go take a look and see that network traffic is at capacity. They've got some 'magic' caching framework that promises to speed things up by storing data in Redis. What's happening in the background though is that this caching framework is doing dumb things like asking for the same key over and over again - so we've got a multi-Gbit stream of the same handful of keys being asked for thousands of times a second. These are the sorts of things profiling can tell you just by looking at the amount of calls to Redis.