From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Chavent <Paul.Chavent@onera.fr>
Subject: Re: [PATCH] net-packet: tx timestamping on tpacket ring
Date: Mon, 15 Apr 2013 09:31:14 +0200
Message-ID: <516BACC2.7060400@onera.fr>
References: <CA+FuTSezggEb7znDYMf8vWU7JmWLP59AVPkaTvNaAwJoNcqk9A@mail.gmail.com> <1365879412-9541-1-git-send-email-willemb@google.com>
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Cc: richardcochran@gmail.com, edumazet@google.com,
	daniel.borkmann@tik.ee.ethz.ch, xemul@parallels.com,
	ebiederm@xmission.com, netdev@vger.kernel.org
To: Willem de Bruijn <willemb@google.com>
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In-Reply-To: <1365879412-9541-1-git-send-email-willemb@google.com>
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Hi.

On 04/13/2013 08:56 PM, Willem de Bruijn wrote:
> [...]
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -3311,7 +3311,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
>   		 * so keep the shared tx_flags and only
>   		 * store software time stamp
>   		 */
> -		skb->tstamp = ktime_get_real();
> +		orig_skb->tstamp = skb->tstamp = ktime_get_real();
>   	}

You said that "the orig_skb is usually freed shortly after
skb_tstamp_tx is called".

So i suppose that if you had coded it, that's because this orig_skb is 
the one that is given to the skb destructor. So when you call 
__packet_set_timestamp, in tpacket_destruct_skb, you get this timestamp 
? Am i right ?


Why we couldn't call
*skb_hwtstamps(orig_skb) = *skb_hwtstamps(skb) = *hwtstamps;
in order to get the hardware timestamping too ?

Thank for your help.

Paul.