Re: Kernel 4.13.0-rc4-next-20170811 - IP Routing / Forwarding performance vs Core/RSS number / HT on
flat view
From: Eric Dumazet <hidden>
Date: 2017-08-14 16:33:09
On Mon, 2017-08-14 at 18:19 +0200, Jesper Dangaard Brouer wrote:
The output (extracted below) didn't show who called 'do_raw_spin_lock',
BUT it showed another interesting thing. The kernel code
__dev_queue_xmit() in might create route dst-cache problem for itself(?),
as it will first call skb_dst_force() and then skb_dst_drop() when the
packet is transmitted on a VLAN.
static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
{
[...]
/* If device/qdisc don't need skb->dst, release it right now while
* its hot in this cpu cache.
*/
if (dev->priv_flags & IFF_XMIT_DST_RELEASE)
skb_dst_drop(skb);
else
skb_dst_force(skb);This is explained in this commit changelog. https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?id=93f154b594fe47e4a7e5358b309add449a046cd3