[dpdk-dev] 答复: [PATCH] Add user defined tag calculation callback tolibrte_distributor.
Bruce Richardson
bruce.richardson at intel.com
Fri Nov 7 15:44:10 CET 2014
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;
>
>
>
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