Thread (7 messages) 7 messages, 5 authors, 2021-02-04

Re: [PATCH v3 bpf-next] net: veth: alloc skb in bulk for ndo_xdp_xmit

From: Jesper Dangaard Brouer <hidden>
Date: 2021-02-02 16:19:35
Also in: netdev

On Fri, 29 Jan 2021 23:04:08 +0100
Lorenzo Bianconi [off-list ref] wrote:
Split ndo_xdp_xmit and ndo_start_xmit use cases in veth_xdp_rcv routine
in order to alloc skbs in bulk for XDP_PASS verdict.
Introduce xdp_alloc_skb_bulk utility routine to alloc skb bulk list.
The proposed approach has been tested in the following scenario:

eth (ixgbe) --> XDP_REDIRECT --> veth0 --> (remote-ns) veth1 --> XDP_PASS

XDP_REDIRECT: xdp_redirect_map bpf sample
XDP_PASS: xdp_rxq_info bpf sample

traffic generator: pkt_gen sending udp traffic on a remote device

bpf-next master: ~3.64Mpps
bpf-next + skb bulking allocation: ~3.79Mpps

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
I wanted Lorenzo to test 8 vs 16 bulking, but after much testing and
IRC dialog, we cannot find and measure any difference with enough
accuracy. Thus:

Acked-by: Jesper Dangaard Brouer <redacted>
quoted hunk ↗ jump to hunk
Changes since v2:
- use __GFP_ZERO flag instead of memset
- move some veth_xdp_rcv_batch() logic in veth_xdp_rcv_skb()

Changes since v1:
- drop patch 2/3, squash patch 1/3 and 3/3
- set VETH_XDP_BATCH to 16
- rework veth_xdp_rcv to use __ptr_ring_consume
---
 drivers/net/veth.c | 78 ++++++++++++++++++++++++++++++++++------------
 include/net/xdp.h  |  1 +
 net/core/xdp.c     | 11 +++++++
 3 files changed, 70 insertions(+), 20 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 6e03b619c93c..aa1a66ad2ce5 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -35,6 +35,7 @@
 #define VETH_XDP_HEADROOM	(XDP_PACKET_HEADROOM + NET_IP_ALIGN)
 
 #define VETH_XDP_TX_BULK_SIZE	16
+#define VETH_XDP_BATCH		16
 

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer
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