From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?N=E9lio?= Laranjeiro Subject: Re: [PATCH] net/mlx5: return RSS hash result in mbuf Date: Tue, 27 Sep 2016 16:29:49 +0200 Message-ID: <20160927142949.GE32397@autoinstall.dev.6wind.com> References: <42701f77fcdb03c88ea845071c0710797cfaa549.1473840791.git.nelio.laranjeiro@6wind.com> <20160927141110.GC36420@bricha3-MOBL3> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: dev@dpdk.org, Adrien Mazarguil To: Bruce Richardson Return-path: Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46]) by dpdk.org (Postfix) with ESMTP id 4EAEA2BA1 for ; Tue, 27 Sep 2016 16:29:57 +0200 (CEST) Received: by mail-wm0-f46.google.com with SMTP id l132so16281034wmf.1 for ; Tue, 27 Sep 2016 07:29:57 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20160927141110.GC36420@bricha3-MOBL3> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Bruce, On Tue, Sep 27, 2016 at 03:11:10PM +0100, Bruce Richardson wrote: > On Wed, Sep 14, 2016 at 10:16:05AM +0200, Nelio Laranjeiro wrote: > > Signed-off-by: Nelio Laranjeiro > > --- > > drivers/net/mlx5/mlx5_rxq.c | 1 + > > drivers/net/mlx5/mlx5_rxtx.c | 6 +++++- > > drivers/net/mlx5/mlx5_rxtx.h | 2 ++ > > 3 files changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c > > index f6f4315..65c264b 100644 > > --- a/drivers/net/mlx5/mlx5_rxq.c > > +++ b/drivers/net/mlx5/mlx5_rxq.c > > @@ -926,6 +926,7 @@ rxq_ctrl_setup(struct rte_eth_dev *dev, struct rxq_ctrl *rxq_ctrl, > > .rxq = { > > .elts_n = log2above(desc), > > .mp = mp, > > + .rss_hash = !!(priv->rxqs_n > 1), > > }, > > Two comments on this: > 1. I don't think the !! is needed, since this is a comparison which will result > in 0 or 1, rather than an int value that needs to be clamped to those values. Ok for this one. > 2. Why limit the use of RSS to when there is more than one RX queues? Sometimes > it might be useful to have a precomputed hash for a packet even when not > spreading packets among RX queues. For example, when using a single RX queue, > but doing a hash table lookup for each packet, the RSS value could be used > as the lookup hash. > > /Bruce ConnectX-4 NICs does not return a hash value for a single queue as software does not request RSS in this situation, that is why it is not filled. I will send a v2 to also fix a bug discovered since concerning the hash result which is not retrieve from the right place when Completion Queue Entry is compressed. Regards, -- Nélio Laranjeiro 6WIND