linux-kernel - RE: [PATCH v2 net-next 4/5] sunvnet: count multicast packets

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Message-ID: <063D6719AE5E284EB5DD2968C1650D6DCFFB12CF@AcuExch.aculab.com>
Date:   Wed, 15 Mar 2017 08:50:05 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Shannon Nelson' <shannon.nelson@...cle.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>
CC:     "sparclinux@...r.kernel.org" <sparclinux@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 net-next 4/5] sunvnet: count multicast packets

From: Shannon Nelson
> Sent: 14 March 2017 17:25
...
> +	if (unlikely(is_multicast_ether_addr(eth_hdr(skb)->h_dest)))
> +		dev->stats.multicast++;

I'd guess that:
	dev->stats.multicast += is_multicast_ether_addr(eth_hdr(skb)->h_dest);
generates faster code.
Especially if is_multicast_ether_addr(x) is (*x >> 7).

	David