From: Tariq Toukan <tariqt@mellanox.com>
Date: Thu, 15 Jun 2017 14:35:40 +0300
Subject: net/mlx4_en: Refactor mlx4_en_free_tx_desc
Patch-mainline: v4.13-rc1
Git-commit: 4c07c132408a685d31bb6e638aef4d245e30703a
References: bsc#1046299 FATE#322947
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 45 ++++++++++-------------------
1 file changed, 16 insertions(+), 29 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -289,20 +289,20 @@ u32 mlx4_en_free_tx_desc(struct mlx4_en_
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_
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 */