Reference for relative operation expense
Does anyone know a good reference to help with understanding the relative cost of operations like copying variables, declaring new variables, FileIO, array operations, etc? I've been told to study decompilat开发者_如何学运维ion and machine code but a quick reference would be nice. For example, something to tell me how much worse
for(int i = 0; i < 100; i++){
new double d = 7.65;
calc(d);
}
is than
double d = 7.65;
for(int i = 0; i < 100; i++){
calc(d);
}
Here is a nice paper by Felix von Leitner on the state of C compiler optimization. I learned of it on this Lambda the Ultimate page.
The performance of operations you mention such as file I/O, memory access, and computation are highly dependent on a computer's architecture. Much of the optimization of software for today's desktop computers is focused on cache memory.
You would gain much from an architecture book or course. Here's a good example from CMU.
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