On Fri, Nov 07, 2014 at 04:31:18PM +0200, jigsaw wrote: > Hi Bruce, > > Pls have a quick look at the diff to see if this is exactly what you mean > about the bitmask. > I just wrote it without even compiling, just to express the idea. So it may > leave some places unpatched. > If this is agreed, I will make a decent test to verify it before sending > the patch for RFC. > > diff --git a/lib/librte_distributor/rte_distributor.c > b/lib/librte_distributor/rte_di > index 585ff88..d606bcf 100644 > --- a/lib/librte_distributor/rte_distributor.c > +++ b/lib/librte_distributor/rte_distributor.c > @@ -92,6 +92,8 @@ struct rte_distributor { > unsigned num_workers; /**< Number of workers > polling */ > > uint32_t in_flight_tags[RTE_MAX_LCORE]; > + uint32_t in_flight_bitmask; > + > struct rte_distributor_backlog backlog[RTE_MAX_LCORE]; > > union rte_distributor_buffer bufs[RTE_MAX_LCORE]; > @@ -188,6 +190,7 @@ static inline void > handle_worker_shutdown(struct rte_distributor *d, unsigned wkr) > { > d->in_flight_tags[wkr] = 0; > + d->in_flight_mask &= ~(1 << wkr); > d->bufs[wkr].bufptr64 = 0; > if (unlikely(d->backlog[wkr].count != 0)) { > /* On return of a packet, we need to move the > @@ -241,6 +244,7 @@ process_returns(struct rte_distributor *d) > else { > d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF; > d->in_flight_tags[wkr] = 0; > + d->in_flight_mask &= ~(1 << wkr); > } > oldbuf = data >> RTE_DISTRIB_FLAG_BITS; > } else if (data & RTE_DISTRIB_RETURN_BUF) { > @@ -282,12 +286,13 @@ rte_distributor_process(struct rte_distributor *d, > next_mb = mbufs[next_idx++]; > next_value = (((int64_t)(uintptr_t)next_mb) > << RTE_DISTRIB_FLAG_BITS); > - new_tag = (next_mb->hash.rss | 1); > + new_tag = next_mb->hash.rss; > > uint32_t match = 0; > unsigned i; > for (i = 0; i < d->num_workers; i++) > - match |= (!(d->in_flight_tags[i] ^ new_tag) > + match |= (((!(d->in_flight_tags[i] ^ > new_tag)) & > + (d->in_flight_bitmask >> i))
I would not do the bitmask comparison here, as that's extra instruction in the loop. Instead, because its a bitmask, build up the match variable as it was before, and then just do a single and operation afterwards, outside the loop body. /Bruce > << i); > > if (match) { > @@ -309,6 +314,7 @@ rte_distributor_process(struct rte_distributor *d, > else { > d->bufs[wkr].bufptr64 = next_value; > d->in_flight_tags[wkr] = new_tag; > + d->in_flight_bitmask |= 1 << wkr; > next_mb = NULL; > } > oldbuf = data >> RTE_DISTRIB_FLAG_BITS; > > >