Em Fri, Aug 26, 2005 at 09:06:22PM -0700, Mitchell Blank Jr escreveu:
> Andi Kleen wrote:
> > - it doesn't seem to help that much on modern CPUs with good
> > branch prediction and big icaches anyways.
>
> Really? I would think that as pipelines get deeper (although that trend
> seems to have stopped, thankfully) and Icache-miss penalties get relatively
> larger we'd see unlikely() becoming MORE of a benefit, not less. Storing
> the used part of a "hot" function in 1 Icacheline instead of 4 seems like
> an obvious win.
>
> Personally I've never found unlikely() to be ugly; if anything I think
> it serves as a nice little human-readable comment about whats going on
> in the control-flow. I guess I'm in the minority on that one, though.
Hey, even if unlikely was:
#define unlikely(x) (x)
I'd find it useful :-)
- Arnaldo
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