iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

net/mlx4_en: Remove RX buffers alignment to IP_ALIGN

Browse Source 
When IP_ALIGN has a non zero value, hardware will write to a non aligned
address. The only reader from this address is when copying the header
from the first frag into the linear buffer (further access to the IP
address will be from the linear buffer, in which the headers are
aligned). Since the penalty of non align access by the hardware is
greater than the software memcpy, changing the frag_align to always be 0.

Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ido Shamay 2014-11-02 16:26:15 +02:00 committed by David S. Miller
parent 0a98455666
commit 5f6e980080
2 changed files with 4 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/net/ethernet/mellanox/mlx4/en_rx.c
View File

@ -74,7 +74,7 @@ static int mlx4_alloc_pages(struct mlx4_en_priv *priv,
page_alloc->page_size = PAGE_SIZE << order;
page_alloc->page = page;
page_alloc->dma = dma;
page_alloc->page_offset = frag_info->frag_align;
page_alloc->page_offset = 0;
/* Not doing get_page() for each frag is a big win
* on asymetric workloads. Note we can not use atomic_set().
*/
@ -945,15 +945,8 @@ void mlx4_en_calc_rx_buf(struct net_device *dev)
(eff_mtu > buf_size + frag_sizes[i]) ?
frag_sizes[i] : eff_mtu - buf_size;
priv->frag_info[i].frag_prefix_size = buf_size;
if (!i) {
priv->frag_info[i].frag_align = NET_IP_ALIGN;
priv->frag_info[i].frag_stride =
ALIGN(frag_sizes[i] + NET_IP_ALIGN, SMP_CACHE_BYTES);
} else {
priv->frag_info[i].frag_align = 0;
priv->frag_info[i].frag_stride =
ALIGN(frag_sizes[i], SMP_CACHE_BYTES);
}
priv->frag_info[i].frag_stride = ALIGN(frag_sizes[i],
SMP_CACHE_BYTES);
buf_size += priv->frag_info[i].frag_size;
i++;
}
@ -966,11 +959,10 @@ void mlx4_en_calc_rx_buf(struct net_device *dev)
eff_mtu, priv->num_frags);
for (i = 0; i < priv->num_frags; i++) {
en_err(priv,
" frag:%d - size:%d prefix:%d align:%d stride:%d\n",
" frag:%d - size:%d prefix:%d stride:%d\n",
i,
priv->frag_info[i].frag_size,
priv->frag_info[i].frag_prefix_size,
priv->frag_info[i].frag_align,
priv->frag_info[i].frag_stride);
}
}

1
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
View File

@ -481,7 +481,6 @@ struct mlx4_en_frag_info {
u16 frag_size;
u16 frag_prefix_size;
u16 frag_stride;
u16 frag_align;
};
#ifdef CONFIG_MLX4_EN_DCB