[Xen-devel] Re: [PATCH RFC V2 3/5] jump_label: if a key has already been initialized, don't nop it out

[Steven Rostedt <rostedt@xxxxxxxxxxx>]

On Thu, 2011-10-06 at 14:39 -0700, Jeremy Fitzhardinge wrote:

> I'm not sure it would be a win, necessarily.  My test with back-to-back
> jmp2 was definitely slower than with the nop padding it out to 5 bytes;
> I suspect that's a result of having too many jmps within one cacheline. 
> Of course, there's no reason why the CPU would optimise for jumps to
> jumps, so perhaps its just hitting a "stupid programmer" path.

Just a note. Micro-benchmarks are known to be as good as political polls
and statistics. They show a much different view of the world than what
is really there.

-- Steve



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel