[ovs-dev] OVS_LIKELY in miniflow_extract()

[Ben Pfaff]

On Thu, May 29, 2014 at 01:56:31PM -0700, Jarno Rajahalme wrote:
> 
> > On May 29, 2014, at 1:03 PM, Ben Pfaff <blp at nicira.com> wrote:
> > 
> > I think that miniflow_extract() goes a little overboard on the
> > OVS_LIKELYs.  In particular these seem suspicious:
> > 
> >            if (OVS_LIKELY((nw_proto != IPPROTO_HOPOPTS)
> >        if (OVS_LIKELY(nw_proto == IPPROTO_TCP)) {
> >        } else if (OVS_LIKELY(nw_proto == IPPROTO_UDP)) {
> >        } else if (OVS_LIKELY(nw_proto == IPPROTO_SCTP)) {
> >        } else if (OVS_LIKELY(nw_proto == IPPROTO_ICMP)) {
> >        } else if (OVS_LIKELY(nw_proto == IPPROTO_ICMPV6)) {
> > 
> > I would put all of these into a single outermost OVS_LIKELY, to make
> > it easier to read:
> >            if (OVS_LIKELY(arp) && OVS_LIKELY(arp->ar_hrd == htons(1))
> >                && OVS_LIKELY(arp->ar_pro == htons(ETH_TYPE_IP))
> >                && OVS_LIKELY(arp->ar_hln == ETH_ADDR_LEN)
> >                && OVS_LIKELY(arp->ar_pln == 4)) {
> > 
> > What do you think?
> 
> You are LIKELY right, and we can always tune these if there is a
> practical difference in generated code.

OK.

Your patch or mine?