How do the likely/unlikely macros in the Linux kernel work and what is their benefit?
I’ve been digging through some parts of the Linux kernel, and found calls like this: if (unlikely(fd < 0)) { /* Do something */ } or if (likely(!err)) { /* Do something */ } I’ve found the definition of them: #define likely(x) __builtin_expect((x),1) #define unlikely(x) __builtin_expect((x),0) I know that they are for optimization, but how … Read more
