Subject: Re: [PATCH net-next-2.6] macvlan: add multiqueue capability

From: Patrick McHardy <[email-masked]>
Date: Thu, 03 Sep 2009 19:54:04 +0200

Eric Dumazet wrote:
> macvlan devices are currently not multi-queue capable.
> 
> We can do that defining rtnl_link_ops method,
> get_tx_queues(), called from rtnl_create_link()
> 
> This new method gets num_tx_queues/real_num_tx_queues
> from lower device.
> 
> macvlan_get_tx_queues() is a copy of vlan_get_tx_queues().
> 
> Because macvlan_start_xmit() has to update netdev_queue
> stats only (and not dev->stats), I chose to change
> tx_errors/tx_aborted_errors accounting to tx_dropped,
> since netdev_queue structure doesnt define tx_errors /
> tx_aborted_errors.

The patch looks fine, but it just occured to me that this won't
have any effect since both VLAN and macvlan use a tx_queue_len of 0,
so they will by default have queueing disabled. In fact this
will increase costs for the default case since we're now hashing
every packet.