linux-kernel - Re: [V2 RFC net-next PATCH 2/2] virtio_net: export more statistics through ethtool

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120608070237.GA32532@redhat.com>
Date:	Fri, 8 Jun 2012 10:02:37 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Jason Wang <jasowang@...hat.com>
Cc:	netdev@...r.kernel.org, rusty@...tcorp.com.au,
	virtualization@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [V2 RFC net-next PATCH 2/2] virtio_net: export more statistics
 through ethtool

On Fri, Jun 08, 2012 at 11:35:25AM +0800, Jason Wang wrote:
> >>>  @@ -655,7 +695,17 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
> >>>    		kfree_skb(skb);
> >>>    		return NETDEV_TX_OK;
> >>>    	}
> >>>  -	virtqueue_kick(vi->svq);
> >>>  +
> >>>  +	kick = virtqueue_kick_prepare(vi->svq);
> >>>  +	if (unlikely(kick))
> >>>  +		virtqueue_notify(vi->svq);
> >>>  +
> >>>  +	u64_stats_update_begin(&stats->syncp);
> >>>  +	if (unlikely(kick))
> >>>  +		stats->data[VIRTNET_TX_KICKS]++;
> >>>  +	stats->data[VIRTNET_TX_Q_BYTES] += skb->len;
> >>>  +	stats->data[VIRTNET_TX_Q_PACKETS]++;
> >is this statistic interesting?
> >how about decrementing when we free?
> >this way we see how many are pending..
> >
> 
> Currently we didn't have per-vq statistics but per-cpu, so the skb
> could be sent by one vcpu and freed by another.
> Pehaps another reason to use per-queue satistics.

For transmit, it could be done easily as we both send and free skbs
under a lock. I'm not sure how acceptable it is to
take a lock in get_stats but send a separate patch like this
and we'll see what others say.

-- 
MST
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/