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Commit f7d3c1cb authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net/mlx4_en: fix ethtool -x 



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: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarMaciej Żenczykowski <maze@google.com>
Cc: Eugenia Emantayev <eugenia@mellanox.com>
Cc: Wei Wang <weiwan@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reviewed-by: default avatarTariq Toukan <tariqt@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c8d83963

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

+12 −13
Original line number Diff line number Diff line
@@ -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))