From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Khlebnikov Subject: [PATCH RFC] net/mlx5_en: switch to Toeplitz RSS hash by default Date: Fri, 31 Aug 2018 14:29:16 +0300 Message-ID: <153571495680.372632.9464993927924201878.stgit@buzz> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org, Saeed Mahameed , Gal Pressman , Or Gerlitz , "David S. Miller" , Tariq Toukan Return-path: Received: from forwardcorp1g.cmail.yandex.net ([87.250.241.190]:49002 "EHLO forwardcorp1g.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726990AbeHaPoQ (ORCPT ); Fri, 31 Aug 2018 11:44:16 -0400 Sender: netdev-owner@vger.kernel.org List-ID: XOR (MLX5_RX_HASH_FN_INVERTED_XOR8) gives only 8 bits. It seems not enough for RFS. All other drivers use toeplitz. Driver mlx4_en uses Toeplitz by default and warns if hash XOR is used together with NETIF_F_RXHASH (enabled by default too): "Enabling both XOR Hash function and RX Hashing can limit RPS functionality". XOR is default in mlx5_en since commit 2be6967cdbc9 ("net/mlx5e: Support ETH_RSS_HASH_XOR"). Hash function could be set via ethtool. But it would be nice to have single standard for drivers or proper description why this one is special. Signed-off-by: Konstantin Khlebnikov --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 5a7939e70190..def9fb5dcbff 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -4558,7 +4558,7 @@ void mlx5e_build_nic_params(struct mlx5_core_dev *mdev, params->tx_min_inline_mode = mlx5e_params_calculate_tx_min_inline(mdev); /* RSS */ - params->rss_hfunc = ETH_RSS_HASH_XOR; + params->rss_hfunc = ETH_RSS_HASH_TOP; netdev_rss_key_fill(params->toeplitz_hash_key, sizeof(params->toeplitz_hash_key)); mlx5e_build_default_indir_rqt(params->indirection_rqt, MLX5E_INDIR_RQT_SIZE, max_channels);