A bit part of the optimization is the flattening of deeply nested calls to tiny functions that are prevalent in the STL. In the general case of STL usage, these calls serve an important purpose in the design and flexibility of the library. They also generally inline away in optimized builds. However, in the specific case of game development, they greatly slow down the performance of non-optimized builds. That performance is a big deal when you are debugging a game that by design stresses the limits of the fixed hardware platform it is running on (you can't upgrade the CPU in a PS3 devkit). The nested inline functions also make debugging much harder because stepping into observe simple actions can result in walking a long chain of calls that each effectively do nothing.
Comments
A bit part of the optimization is the flattening of deeply nested calls to tiny functions that are prevalent in the STL. In the general case of STL usage, these calls serve an important purpose in the design and flexibility of the library. They also generally inline away in optimized builds. However, in the specific case of game development, they greatly slow down the performance of non-optimized builds. That performance is a big deal when you are debugging a game that by design stresses the limits of the fixed hardware platform it is running on (you can't upgrade the CPU in a PS3 devkit). The nested inline functions also make debugging much harder because stepping into observe simple actions can result in walking a long chain of calls that each effectively do nothing.