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net/mlx4_en: Refactor mlx4_en_free_tx_desc 

Some code re-ordering, functionally equivalent.

- The !tx_info->inl check is evaluated anyway in both flows
  (common case/end case). Run it first, this might finish
  the flows earlier.
- dma_unmap calls are identical in both flows, get it out
  of the if block into the common area.

Performance tests:
Tested on ConnectX3Pro, Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz

Gain is too small to be measurable, no degradation sensed.
Results are similar for IPv4 and IPv6.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Cc: kernel-team@fb.com
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tariq Toukan 2017-06-15 14:35:40 +03:00 committed by David S. Miller
parent 9573e0d39f
commit 4c07c13240
1 changed files with 16 additions and 29 deletions
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45
drivers/net/ethernet/mellanox/mlx4/en_tx.c
View File

@ -289,20 +289,20 @@ u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
skb_tstamp_tx(skb, &hwts);
}
/* Optimize the common case when there are no wraparounds */
if (likely((void *)tx_desc +
(tx_info->nr_txbb << LOG_TXBB_SIZE) <= end)) {
if (!tx_info->inl) {
if (tx_info->linear)
dma_unmap_single(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
else
dma_unmap_page(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
if (!tx_info->inl) {
if (tx_info->linear)
dma_unmap_single(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
else
dma_unmap_page(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
/* Optimize the common case when there are no wraparounds */
if (likely((void *)tx_desc +
(tx_info->nr_txbb << LOG_TXBB_SIZE) <= end)) {
for (i = 1; i < nr_maps; i++) {
data++;
dma_unmap_page(priv->ddev,
@ -310,23 +310,10 @@ u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
be32_to_cpu(data->byte_count),
PCI_DMA_TODEVICE);
}
}
} else {
if (!tx_info->inl) {
if ((void *) data >= end) {
} else {
if ((void *)data >= end)
data = ring->buf + ((void *)data - end);
}
if (tx_info->linear)
dma_unmap_single(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
else
dma_unmap_page(priv->ddev,
tx_info->map0_dma,
tx_info->map0_byte_count,
PCI_DMA_TODEVICE);
for (i = 1; i < nr_maps; i++) {
data++;
/* Check for wraparound before unmapping */