From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eyal perry Subject: Re: [PATCH net-next 2/2] net/mlx4_en: Support for configurable RSS hash function Date: Wed, 05 Nov 2014 15:05:52 +0200 Message-ID: <545A20B0.4080807@dev.mellanox.co.il> References: <1415188769-19593-1-git-send-email-amirv@mellanox.com> <1415188769-19593-3-git-send-email-amirv@mellanox.com> <545A17C2.9070609@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Amir Vadai , "David S. Miller" , Ben Hutchings , netdev@vger.kernel.org, Yevgeny Petrilin To: Or Gerlitz , Eyal Perry Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:51073 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbaKENF6 (ORCPT ); Wed, 5 Nov 2014 08:05:58 -0500 Received: by mail-wi0-f174.google.com with SMTP id d1so12355830wiv.1 for ; Wed, 05 Nov 2014 05:05:57 -0800 (PST) In-Reply-To: <545A17C2.9070609@mellanox.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/5/2014 2:27 PM, Or Gerlitz wrote: > On 11/5/2014 1:59 PM, Amir Vadai wrote: >> From: Eyal Perry >> >> The ConnectX HW is capable of using one of the following hash functions: >> Toeplitz and an XOR hash function. >> This patch implements ethtool_ops {get,set}_rxfh_func callbacks for the >> mlx4_en driver in order to query and configure the RSS hash function to >> be used by the device. >> >> Signed-off-by: Eyal Perry >> Signed-off-by: Amir Vadai >> --- >> drivers/net/ethernet/mellanox/mlx4/en_ethtool.c | 40 >> +++++++++++++++++++++++++ >> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 9 ++++++ >> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 11 ++++--- >> drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 +- >> 4 files changed, 58 insertions(+), 5 deletions(-) >> [...] >> + >> +static int mlx4_en_set_rxfh_func(struct net_device *dev, u32 hfunc) >> +{ >> + struct mlx4_en_priv *priv = netdev_priv(dev); >> + struct mlx4_en_dev *mdev = priv->mdev; >> + u32 prev_rss_hash_fn = priv->rss_hash_fn; >> + int err = 0; >> + >> + if (!(hfunc & priv->rss_hash_fn_caps)) >> + return -EINVAL; >> + >> + priv->rss_hash_fn = hfunc; > > Seems that you are blindly setting here priv->rss_hash_fn to the > function (xor or top) requested > by the user w.o prior checking if the firmware actually supports that > (e.g test it against priv->rss_hash_fn_caps, right? > That exactly what I do 3 lines above, priv->rss_hash_fn_caps is derived from firmware capabilities. [...] >> --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c >> +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c >> @@ -1113,10 +1113,13 @@ int mlx4_en_config_rss_steer(struct >> mlx4_en_priv *priv) >> } >> rss_context->flags = rss_mask; >> - rss_context->hash_fn = MLX4_RSS_HASH_TOP; >> - for (i = 0; i < 10; i++) >> - rss_context->rss_key[i] = cpu_to_be32(rsskey[i]); >> - >> + if (priv->rss_hash_fn & MLX4_RSS_HASH_XOR) { >> + rss_context->hash_fn = MLX4_RSS_HASH_XOR; >> + } else { >> + rss_context->hash_fn = MLX4_RSS_HASH_TOP; >> + for (i = 0; i < 10; i++) >> + rss_context->rss_key[i] = cpu_to_be32(rsskey[i]); >> + } > > So this patch effectively changes the default from top to xor, right? is > that intentional? if yes, spare few words on the change log. > No, in general the default shouldn't be affected by the patch (unless there's a bug). The default value is set in mlx4_en_init_netdev() and it will remain Toeplitz unless firmware is supports only XOR hash function. [...]