netgraph: why does ng_ether bother enqueuing packets?

[Vincent Jardin]

Le Mercredi 21 Mai 2003 23:03, Dave Dolson a écrit :
> For reasons of performance, I tried the following modification to
> ng_ether.c in FreeBSD 4.7, and it seemed to work fine.
> The change is to call ng_send_data() vs. ng_queue_data().
>
> We are running in polling mode, so ng_ether_input is called @ netisr
> anyhow. (Always ?)

What's about the ng_ether's node that are created on the ethernet interfaces 
that do not support polling ?

>
>   static void
>   ng_ether_input2(node_p node, struct mbuf **mp, struct ether_header *eh)
>   {
>         const priv_p priv = node->private;
>         meta_p meta = NULL;
>         int error;
>
>         /* Glue Ethernet header back on */
>         if ((error = ng_ether_glueback_header(mp, eh)) != 0)
>                 return;
>
>         /* Send out lower/orphan hook */
> + #ifdef DEVICE_POLLING
> +       /* send directly, since we're already @ splnet */
> +       (void)ng_send_data(priv->lower, *mp, meta);
> + #else
>         (void)ng_queue_data(priv->lower, *mp, meta);
> + #endif
>         *mp = NULL;
>   }
>
> Does anyone know why this might be bad?
> Any reason why this couldn't be done in interrupt (non-polling) mode also?
>
> The system's main purpose is to process packets.
>
> Thanks,
> David Dolson (ddolson at sandvine.com, www.sandvine.com)
>
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