* Linus Torvalds (torva...@linux-foundation.org) wrote: [...] > With two-byte jumps, you'd still get the I$ fragmentation (the > argument generation and the call and the branch back would all be in > the same code segment as the hot code), but that would be offset by > the fact that at least the hot code itself could use a short jump when > possible (ie a 2-byte nop rather than a 5-byte one).
I remember that choosing between 2 and 5 bytes nop in the asm goto was tricky: it had something to do with the fact that gcc doesn't know the exact size of each instructions until further down within compilation phases on architectures with variable instruction size like x86. If we have guarantees that the guessed size of each instruction is an upper bound on the instruction size, this could probably work though. Thoughts ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
