[PATCH net-next 2/2] mvpp2: prefetch page
From: Matteo Croce <hidden>
Date: 2021-06-09 13:48:22
Also in:
lkml
Subsystem:
marvell mvpp2 ethernet driver, networking drivers, the rest · Maintainers:
Marcin Wojtas, Russell King, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Matteo Croce <redacted>
Most of the time during the RX is caused by the compound_head() call
done at the end of the RX loop:
│ build_skb():
[...]
│ static inline struct page *compound_head(struct page *page)
│ {
│ unsigned long head = READ_ONCE(page->compound_head);
65.23 │ ldr x2, [x1, #8]
Prefetch the page struct as soon as possible, to speedup the RX path
noticeabily by a ~3-4% packet rate in a drop test.
│ build_skb():
[...]
│ static inline struct page *compound_head(struct page *page)
│ {
│ unsigned long head = READ_ONCE(page->compound_head);
17.92 │ ldr x2, [x1, #8]
Signed-off-by: Matteo Croce <redacted>
---
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 07d8f3e31b52..9bca8c8f9f8d 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c@@ -3900,15 +3900,19 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi, phys_addr_t phys_addr; u32 rx_status, timestamp; int pool, rx_bytes, err, ret; + struct page *page; void *data; + phys_addr = mvpp2_rxdesc_cookie_get(port, rx_desc); + data = (void *)phys_to_virt(phys_addr); + page = virt_to_page(data); + prefetch(page); + rx_done++; rx_status = mvpp2_rxdesc_status_get(port, rx_desc); rx_bytes = mvpp2_rxdesc_size_get(port, rx_desc); rx_bytes -= MVPP2_MH_SIZE; dma_addr = mvpp2_rxdesc_dma_addr_get(port, rx_desc); - phys_addr = mvpp2_rxdesc_cookie_get(port, rx_desc); - data = (void *)phys_to_virt(phys_addr); pool = (rx_status & MVPP2_RXD_BM_POOL_ID_MASK) >> MVPP2_RXD_BM_POOL_ID_OFFS;
@@ -3997,7 +4001,7 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi, } if (pp) - skb_mark_for_recycle(skb, virt_to_page(data), pp); + skb_mark_for_recycle(skb, page, pp); else dma_unmap_single_attrs(dev->dev.parent, dma_addr, bm_pool->buf_size, DMA_FROM_DEVICE,
--
2.31.1