Re: [dpdk-dev] 答复: [PATCH] Add user defined tag calculation callback tolibrte_distributor.

[jigsaw <jigsaw@gmail.com>]

OK thanks Bruce. I will get the patch done in coming week. -qinglai

On Fri, Nov 7, 2014 at 5:04 PM, Bruce Richardson <bruce.richardson@intel.com
> wrote:

> On Fri, Nov 07, 2014 at 04:52:46PM +0200, jigsaw wrote:
> > Yeah that's better. As below, right?
>
> Yep.
>
> >
> > @@ -290,6 +294,7 @@ rte_distributor_process(struct rte_distributor *d,
> >                                 match |= (!(d->in_flight_tags[i] ^
> new_tag)
> >                                         << i);
> >
> > +                       match &= d->in_flight_bitmask;
> >                         if (match) {
> >                                 next_mb = NULL;
> >                                 unsigned worker = __builtin_ctz(match);
> >
> >
> > On Fri, Nov 7, 2014 at 4:44 PM, Bruce Richardson <
> bruce.richardson@intel.com
> > > wrote:
> >
> > > 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;
> > > >
> > > >
> > > >
> > >
>