# Re: 100% CPU load when generating traffic to destination network that nexthop is not reachable

- From: Julian Anastasov \<ja@ssi.bg\>
- Date: 2017-08-15 22:11:29 
- List: netdev
- Page: https://ratatoskr.run/netdev/2017/08/11062771
- Thread: https://ratatoskr.run/netdev/2017/08/11062736/t.md

```text

	Hello,

On Wed, 16 Aug 2017, Julian Anastasov wrote:

> 	I thought about this, it is possible in
> neigh_event_send:
> 
>         if (neigh->used != now)
>                 neigh->used = now;
> 	else if (neigh->nud_state == NUD_INCOMPLETE &&
> 		 neigh->arp_queue_len_bytes + skb->truesize >
> 		 NEIGH_VAR(neigh->parms, QUEUE_LEN_BYTES)

	With kfree_skb(skb) here, of course...

> 		return 1;
> 
> 	But this is really in fast path and not sure it is
> worth it. May be if we can move it somehow in __neigh_event_send
> but as neigh->used is changed early we need a better idea
> how to reduce the arp_queue hit rate...

Regards
```