[dpdk-dev] rte_mbuf library likely()/unlikely()

[Olivier Matz]

Hi,

On Mon, Jul 23, 2018 at 10:40:03PM +0000, Wiles, Keith wrote:
> 
> 
> > On Jul 23, 2018, at 2:09 PM, Morten Brørup <mb at smartsharesystems.com> wrote:
> > 
> > I haven't performance tested, but they are compiler branch prediction hints pointing out the most likely execution path, so I expect them to have a positive effect.
> 
> We really need to make sure this provides any performance improvement and that means it needs to be tested on a number of systems. Can you please do some performance testing or see if we can get the guys doing DPDK performance testing to first give this a try? This area is very sensitive to tweaking.

I agree we should be driven by performance improvements.

I remember a discussion with Bruce on the ML saying that hardware branch
predictors generally do a good job.

Thanks,
Olivier