Re: [dpdk-dev] [PATCH] net/mlx5: fix Rx descriptor status returned value

[Didier Pallard <didier.pallard@6wind.com>]

Hi slava,

Is this fixed in main branch now?
If yes could you please point me out the proper commit?

Thanks
Didier

On 3/17/20 10:25 AM, Slava Ovsiienko wrote:
>
> *From:* Didier Pallard <didier.pallard@6wind.com>
> *Sent:* Tuesday, March 17, 2020 11:19
> *To:* Slava Ovsiienko <viacheslavo@mellanox.com>
> *Cc:* dev@dpdk.org; stable@dpdk.org; Matan Azrad <matan@mellanox.com>
> *Subject:* Re: [dpdk-dev] [PATCH] net/mlx5: fix Rx descriptor status 
> returned value
>
> >>>well, please do if you don't mind,
>
> OK, I will.
>
> >>>You will validate it quicker, and I'm currently working on a 
> different topic.
>
> >>>Btw, do you think it's possible to have an implementation of 
> [r,t]x_status_descriptor functions for vectorized implementation?
>
> >>>thanks
>
> Yes, we are planning this update.
>
> With best regards, Slava
>
> didier
>
> On Tue, Mar 17, 2020 at 9:33 AM Slava Ovsiienko 
> <viacheslavo@mellanox.com <mailto:viacheslavo@mellanox.com>> wrote:
>
>     >> From: Didier Pallard <didier.pallard@6wind.com
>     <mailto:didier.pallard@6wind.com>>
>     >> Sent: Monday, March 16, 2020 19:24
>     >> To: Slava Ovsiienko <viacheslavo@mellanox.com
>     <mailto:viacheslavo@mellanox.com>>
>     >> Cc: dev@dpdk.org <mailto:dev@dpdk.org>; stable@dpdk.org
>     <mailto:stable@dpdk.org>; Matan Azrad <matan@mellanox.com
>     <mailto:matan@mellanox.com>>
>     >> Subject: Re: [dpdk-dev] [PATCH] net/mlx5: fix Rx descriptor
>     status returned value
>     >> Well, you're right, another way to fix the problem could be to
>     set up the queue size assuming the provided number
>     >> is a number of packets in queue rather than a number of mbufs
>     in queue.
>
>     Yes, it is intended in queue setup routine. But, for mlx5 we have
>     a bug for regular mlx5_rx_burst if scattering is enabled,
>     the Rx queue is created with size wqe_n elements, should be wqe_n
>     << sges_n instead, to be able to receive the requested
>     number of packets (wqe_n). I think we must fix. Would you like to
>     update your patch, or should I provide mine?
>
>     >> But not sure it's better, it's also important for the
>     application/user to know the number of mbufs that could fit in a
>     rx/tx queue,
>     >> whatever the number of packets that it covers, since it is very
>     important to size the memory pools correctly to avoid any
>     >> mbuf shortage during system life.
>     >> Thanks
>     >> Didier
>     To estimate - the number of "DPDK descriptors" should be
>     multiplied by the maximal length of scattered packet chain.
>
>     With best regards, Slava
>
>     > -----Original Message-----
>     > From: dev <mailto:dev-bounces@dpdk.org
>     <mailto:dev-bounces@dpdk.org>> On Behalf Of Didier Pallard
>     > Sent: Friday, March 13, 2020 11:57
>     > To: mailto:dev@dpdk.org <mailto:dev@dpdk.org>
>     > Cc: mailto:stable@dpdk.org <mailto:stable@dpdk.org>
>     > Subject: [dpdk-dev] [PATCH] net/mlx5: fix Rx descriptor status
>     returned value
>     >
>     > Two bugs in rx_queue_count function:
>     > - One entry may contain several segments, so 'used' must be
>     multiplied
>     >   by number of segments per entry to properly reflect the queue
>     usage.
>     > - rx_queue_count returns the number of entries used in queue, so
>     it ranges
>     >   from 0 to max number of entries in queue, not this number minus
>     >   one.
>     >
>     > Fixes: 8788fec1f269 ("net/mlx5: implement descriptor status API")
>     > Cc: mailto:stable@dpdk.org <mailto:stable@dpdk.org>
>     > Signed-off-by: Didier Pallard <mailto:didier.pallard@6wind.com
>     <mailto:didier.pallard@6wind.com>>
>     > ---
>     >  drivers/net/mlx5/mlx5_rxtx.c | 2 +-
>     >  1 file changed, 1 insertion(+), 1 deletion(-)
>     >
>     > diff --git a/drivers/net/mlx5/mlx5_rxtx.c
>     b/drivers/net/mlx5/mlx5_rxtx.c index
>     > 5ac63da8039d..17f80c25443e 100644
>     > --- a/drivers/net/mlx5/mlx5_rxtx.c
>     > +++ b/drivers/net/mlx5/mlx5_rxtx.c
>     > @@ -500,7 +500,7 @@ rx_queue_count(struct mlx5_rxq_data *rxq)
>     >               used += n;
>     >               cqe = &(*rxq->cqes)[cq_ci & cqe_cnt];
>     >       }
>     > -     used = RTE_MIN(used, (1U << rxq->elts_n) - 1);
>     > +     used = RTE_MIN(used * (1 << rxq->sges_n), 1U << rxq->elts_n);
>     >       return used;
>     >  }
>     >
>     > --
>     > 2.24.1
>