From f7d3c1cbe34bfcb3eb94a80409ed2577394d0d28 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 7 Jun 2016 21:24:18 -0700 Subject: [PATCH] net/mlx4_en: fix ethtool -x MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit mlx4 RSS is limited to spread incoming packets to a power of two number of queues. An uniformly distibuted traffic would be split on queues 0 to N-1, N being a power of two, each queue having a 1/N weight. If number of RX queues is not a power of two, upper RX queues do not receive traffic. ethtool -x is lying, because it pretends some queues have higher weight. Before patch: lpaa24:~# ethtool -L eth1 rx 24 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 8 9 10 11 12 13 14 15 16: 0 1 2 3 4 5 6 7 RSS hash key: e0:7c:3a:89:07:55:b6:58:69:cc:f4:e5:24:62:e3:25:88:6c:42:5b:d2:cb:9a:d2:e0:06:e1:dc:f9:09:a1:89:0f:a0:30:43:73:6f:0c:b6 If this information was correct, user space tools could expect queues 0 to 7 to receive twice more traffic than queues 8 to 15 After patch : lpaa24:~# ethtool -L eth1 rx 24 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 8 9 10 11 12 13 14 15 RSS hash key: da:7b:09:60:f1:ac:67:b4:d0:72:d4:ec:a2:e5:80:0a:ad:50:22:1a:f8:f9:66:54:5f:22:45:c3:88:f4:57:82:c1:c1:90:ed:70:cb:40:ce lpaa24:~# ethtool -X eth1 equal 8 lpaa24:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 24 RX ring(s): 0: 0 1 2 3 4 5 6 7 8: 0 1 2 3 4 5 6 7 RSS hash key: da:7b:09:60:f1:ac:67:b4:d0:72:d4:ec:a2:e5:80:0a:ad:50:22:1a:f8:f9:66:54:5f:22:45:c3:88:f4:57:82:c1:c1:90:ed:70:cb:40:ce Signed-off-by: Eric Dumazet Reported-by: Maciej Żenczykowski Cc: Eugenia Emantayev Cc: Wei Wang Cc: Willem de Bruijn Reviewed-by: Tariq Toukan Signed-off-by: David S. Miller --- .../net/ethernet/mellanox/mlx4/en_ethtool.c | 25 +++++++++---------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c index fc95affaf76b..51a2e8252b82 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c @@ -1107,7 +1107,7 @@ static u32 mlx4_en_get_rxfh_indir_size(struct net_device *dev) { struct mlx4_en_priv *priv = netdev_priv(dev); - return priv->rx_ring_num; + return rounddown_pow_of_two(priv->rx_ring_num); } static u32 mlx4_en_get_rxfh_key_size(struct net_device *netdev) @@ -1141,19 +1141,17 @@ static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key, u8 *hfunc) { struct mlx4_en_priv *priv = netdev_priv(dev); - struct mlx4_en_rss_map *rss_map = &priv->rss_map; - int rss_rings; - size_t n = priv->rx_ring_num; + u32 n = mlx4_en_get_rxfh_indir_size(dev); + u32 i, rss_rings; int err = 0; - rss_rings = priv->prof->rss_rings ?: priv->rx_ring_num; - rss_rings = 1 << ilog2(rss_rings); + rss_rings = priv->prof->rss_rings ?: n; + rss_rings = rounddown_pow_of_two(rss_rings); - while (n--) { + for (i = 0; i < n; i++) { if (!ring_index) break; - ring_index[n] = rss_map->qps[n % rss_rings].qpn - - rss_map->base_qpn; + ring_index[i] = i % rss_rings; } if (key) memcpy(key, priv->rss_key, MLX4_EN_RSS_KEY_SIZE); @@ -1166,6 +1164,7 @@ static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index, const u8 *key, const u8 hfunc) { struct mlx4_en_priv *priv = netdev_priv(dev); + u32 n = mlx4_en_get_rxfh_indir_size(dev); struct mlx4_en_dev *mdev = priv->mdev; int port_up = 0; int err = 0; @@ -1175,18 +1174,18 @@ static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index, /* Calculate RSS table size and make sure flows are spread evenly * between rings */ - for (i = 0; i < priv->rx_ring_num; i++) { + for (i = 0; i < n; i++) { if (!ring_index) - continue; + break; if (i > 0 && !ring_index[i] && !rss_rings) rss_rings = i; - if (ring_index[i] != (i % (rss_rings ?: priv->rx_ring_num))) + if (ring_index[i] != (i % (rss_rings ?: n))) return -EINVAL; } if (!rss_rings) - rss_rings = priv->rx_ring_num; + rss_rings = n; /* RSS table size must be an order of 2 */ if (!is_power_of_2(rss_rings))