Hi Cristian,
[...]
On Thu, Dec 20, 2018 at 11:28:01AM +0000, Dumitrescu, Cristian wrote:
> > > + * @param m
> > > + * Mbuf to read
> > > + * @param queue_id
> > > + * Returns the queue id
> > > + * @param traffic_class
> > > + * Returns the traffic class id
> > > + * @param color
> > > + * Returns the colour id
> > > + */
> > > +static inline void
> > > +rte_mbuf_sched_get(const struct rte_mbuf *m, uint32_t *queue_id,
> > > + uint8_t *traffic_class,
> > > + uint8_t *color)
> > > +{
> > > + struct rte_mbuf_sched sched = m->hash.sched;
> > > +
> > > + *queue_id = sched.queue_id;
> > > + *traffic_class = sched.traffic_class;
> > > + *color = sched.color;
> >
> > I don't think there is a need to have an additional local copy.
> >
> > *queue_id = m->hash.sched.queue_id;
> > *traffic_class = m->hash.sched.traffic_class;
> > *color = m->hash.sched.color;
> >
>
> With local copy, compiler typically generates a single 8-byte read
> instruction. Without the local copy, compiler typically generates 3x read
> instructions.
>
> The set/get functions are used in some performance critical actions, so this
> is the reason to make sure we get them right.
Ok, that makes sense, thanks for clarification.
Regards,
Olivier
