When receiving traffic, eth_type_trans() is high up on the perf top list,
because it's the first function which access the packet data.
Move the DMA unmap a bit higher, and put a prefetch just after it, so we
have more time to load the data into the cache.
The packet rate increase is about 13% with a tc drop test: 1620 => 1830 kpps
Signed-off-by: Matteo Croce <mcr...@redhat.com>
---
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 111b3b8239e1..17378e0d8da1 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -2966,6 +2966,11 @@ static int mvpp2_rx(struct mvpp2_port *port, struct
napi_struct *napi,
continue;
}
+ dma_unmap_single(dev->dev.parent, dma_addr,
+ bm_pool->buf_size, DMA_FROM_DEVICE);
+
+ prefetch(data);
+
if (bm_pool->frag_size > PAGE_SIZE)
frag_size = 0;
else
@@ -2983,9 +2988,6 @@ static int mvpp2_rx(struct mvpp2_port *port, struct
napi_struct *napi,
goto err_drop_frame;
}
- dma_unmap_single(dev->dev.parent, dma_addr,
- bm_pool->buf_size, DMA_FROM_DEVICE);
-
rcvd_pkts++;
rcvd_bytes += rx_bytes;
--
2.21.0
