diff options
| author | Rosen Penev <rosenp@gmail.com> | 2026-05-22 00:59:08 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-26 00:12:01 +0300 |
| commit | da91508bdd1d4438d431bf7f95de85968cce3f0e (patch) | |
| tree | e9776f3dec1c209a8a91d258a89986ddeec3b6b6 | |
| parent | 0e235b105578389c85b5d0415bc076ed50cbd3f4 (diff) | |
| download | linux-da91508bdd1d4438d431bf7f95de85968cce3f0e.tar.xz | |
net: ibm: emac: Use napi_gro_receive() for Rx packets
emac_poll_rx() already runs in NAPI context and TAH-equipped EMACs set
CHECKSUM_UNNECESSARY on verified frames, which lets GRO coalesce TCP
segments without a software checksum on the merge path. Replace the
per-poll rx_list batched with netif_receive_skb_list() with direct
napi_gro_receive() calls so the stack can merge segments into super-skbs
and skip a full traversal per packet -- a meaningful win on the slow
4xx-class CPUs this driver targets.
Small routing speed improvement tested on a Cisco Meraki MX60W:
Tested with iperf3
Before:
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 494 MBytes 414 Mbits/sec 839 sender
[ 5] 0.00-10.04 sec 492 MBytes 411 Mbits/sec receiver
After:
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 510 MBytes 428 Mbits/sec 580 sender
[ 5] 0.00-10.04 sec 508 MBytes 424 Mbits/sec receiver
Traffic to and from the router seems to be slow no matter what:
Tested with iperf3 --bidir
Before:
[ ID][Role] Interval Transfer Bitrate Retr
[ 8][TX-C] 0.00-10.00 sec 297 MBytes 249 Mbits/sec 35 sender
[ 8][TX-C] 0.00-10.00 sec 293 MBytes 245 Mbits/sec receiver
[ 10][RX-C] 0.00-10.00 sec 184 MBytes 154 Mbits/sec 0 sender
[ 10][RX-C] 0.00-10.00 sec 184 MBytes 154 Mbits/sec receiver
After:
[ ID][Role] Interval Transfer Bitrate Retr
[ 8][TX-C] 0.00-10.00 sec 295 MBytes 248 Mbits/sec 31 sender
[ 8][TX-C] 0.00-10.00 sec 294 MBytes 246 Mbits/sec receiver
[ 10][RX-C] 0.00-10.00 sec 181 MBytes 152 Mbits/sec 0 sender
[ 10][RX-C] 0.00-10.00 sec 181 MBytes 152 Mbits/sec receiver
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20260521215908.257118-1-rosenp@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/ibm/emac/core.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/net/ethernet/ibm/emac/core.c b/drivers/net/ethernet/ibm/emac/core.c index 417dfa18daae..7216209211d9 100644 --- a/drivers/net/ethernet/ibm/emac/core.c +++ b/drivers/net/ethernet/ibm/emac/core.c @@ -1727,7 +1727,6 @@ static inline int emac_rx_sg_append(struct emac_instance *dev, int slot) /* NAPI poll context */ static int emac_poll_rx(void *param, int budget) { - LIST_HEAD(rx_list); struct emac_instance *dev = param; int slot = dev->rx_slot, received = 0; @@ -1784,7 +1783,7 @@ static int emac_poll_rx(void *param, int budget) skb->protocol = eth_type_trans(skb, dev->ndev); emac_rx_csum(dev, skb, ctrl); - list_add_tail(&skb->list, &rx_list); + napi_gro_receive(&dev->mal->napi, skb); next: ++dev->stats.rx_packets; skip: @@ -1828,8 +1827,6 @@ static int emac_poll_rx(void *param, int budget) goto next; } - netif_receive_skb_list(&rx_list); - if (received) { DBG2(dev, "rx %d BDs" NL, received); dev->rx_slot = slot; |