Rely on netif_receive_skb_list routine to send skbs converted from
xdp_frames in cpu_map_kthread_run in order to improve i-cache usage.
The proposed patch has been tested running xdp_redirect_cpu bpf sample
available in the kernel tree that is used to redirect UDP frames from
ixgbe driver to a cpumap entry and then to the networking stack.
UDP frames are generated using pkt_gen.
$xdp_redirect_cpu --cpu <cpu> --progname xdp_cpu_map0 --dev <eth>
bpf-next: ~2.2Mpps
bpf-next + cpumap skb-list: ~3.15Mpps
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
kernel/bpf/cpumap.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 0cf2791d5099..b33114ce2e2b 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -257,6 +257,7 @@ static int cpu_map_kthread_run(void *data)
void *frames[CPUMAP_BATCH];
void *skbs[CPUMAP_BATCH];
int i, n, m, nframes;
+ LIST_HEAD(list);
/* Release CPU reschedule checks */
if (__ptr_ring_empty(rcpu->queue)) {
@@ -305,7 +306,6 @@ static int cpu_map_kthread_run(void *data)
for (i = 0; i < nframes; i++) {
struct xdp_frame *xdpf = frames[i];
struct sk_buff *skb = skbs[i];
- int ret;
skb = __xdp_build_skb_from_frame(xdpf, skb,
xdpf->dev_rx);
@@ -314,11 +314,10 @@ static int cpu_map_kthread_run(void *data)
continue;
}
- /* Inject into network stack */
- ret = netif_receive_skb_core(skb);
- if (ret == NET_RX_DROP)
- drops++;
+ list_add_tail(&skb->list, &list);
}
+ netif_receive_skb_list(&list);
+
/* Feedback loop via tracepoint */
trace_xdp_cpumap_kthread(rcpu->map_id, n, drops, sched, &stats);
--
2.30.2
