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net: mvneta: avoid possible cache misses in mvneta_rx_swbm 

Do not use rx_desc pointers if possible since rx descriptors are stored in
uncached memory and dereferencing rx_desc pointers generate extra loads.
This patch improves XDP_DROP performance of ~ 110Kpps (700Kpps vs 590Kpps)
on Marvell Espressobin

Analyzed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Lorenzo Bianconi 2020-09-29 23:58:57 +02:00 committed by David S. Miller
parent 2b2706aaae
commit 879456bedb
1 changed files with 6 additions and 6 deletions
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12
drivers/net/ethernet/marvell/mvneta.c
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@ -2236,19 +2236,22 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
enum dma_data_direction dma_dir; enum dma_data_direction dma_dir;
struct skb_shared_info *sinfo; struct skb_shared_info *sinfo;
if (rx_desc->data_size > MVNETA_MAX_RX_BUF_SIZE) { if (*size > MVNETA_MAX_RX_BUF_SIZE) {
len = MVNETA_MAX_RX_BUF_SIZE; len = MVNETA_MAX_RX_BUF_SIZE;
data_len += len; data_len += len;
} else { } else {
len = rx_desc->data_size; len = *size;
data_len += len - ETH_FCS_LEN; data_len += len - ETH_FCS_LEN;
} }
*size = *size - len;
dma_dir = page_pool_get_dma_dir(rxq->page_pool); dma_dir = page_pool_get_dma_dir(rxq->page_pool);
dma_sync_single_for_cpu(dev->dev.parent, dma_sync_single_for_cpu(dev->dev.parent,
rx_desc->buf_phys_addr, rx_desc->buf_phys_addr,
len, dma_dir); len, dma_dir);
rx_desc->buf_phys_addr = 0;
/* Prefetch header */ /* Prefetch header */
prefetch(data); prefetch(data);
@ -2259,9 +2262,6 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
sinfo = xdp_get_shared_info_from_buff(xdp); sinfo = xdp_get_shared_info_from_buff(xdp);
sinfo->nr_frags = 0; sinfo->nr_frags = 0;
*size = rx_desc->data_size - len;
rx_desc->buf_phys_addr = 0;
} }
static void static void
@ -2375,7 +2375,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
size = rx_desc->data_size; size = rx_desc->data_size;
frame_sz = size - ETH_FCS_LEN; frame_sz = size - ETH_FCS_LEN;
desc_status = rx_desc->status; desc_status = rx_status;
mvneta_swbm_rx_frame(pp, rx_desc, rxq, &xdp_buf, mvneta_swbm_rx_frame(pp, rx_desc, rxq, &xdp_buf,
&size, page); &size, page);