On Tue, Sep 30, 2014 at 10:09 PM, Sebastian Lackner <sebast...@fds-team.de> wrote: >> + testl $X86_EFLAGS_NT,EFLAGS(%rsp) /* saved EFLAGS match cpu */ >> + jz 1f >> + pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED) >> + popfq_cfi >> +1: >> + > > Do you think it makes sense to change the order here, so that no jump happens > if > NT is not set (which happens a bit more often, than the other way round)? > Just a > guess though, haven't measured if pipeline effects have such a big influence > in this > case. ;) >
It should be immeasurable in a tight loop, since it will predict correctly almost every time. And, unless cfi state works across .pushsection (does it?), getting the cfi annotations right will be more complicated. --Andy -- Andy Lutomirski AMA Capital Management, LLC -- 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/
