svn commit: r238818 - head/sys/dev/netmap

[Bruce Evans]

On Fri, 27 Jul 2012, Luigi Rizzo wrote:

> On Thu, Jul 26, 2012 at 11:39:59PM +0200, Roman Divacky wrote:
>> Why dont you use __builtin_prefetch() ?
>
> ignorance :)
>
> thanks for the pointer, i'll look at it.
> i suppose it works for clang too ?

Even gcc-3.3.1 has it (I expected it not to).  And it works quite
well (defaults to nothing from -mi386, and gives prefetcht0 for
-march=athlon-xp and later).  Other builtins that I have tried
didn't work so well (IIRC, many generate a call to a library
function instead of nothing, when the CPU or compiler doesn't
really support them).

Bruce