From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org, fitz@cs.yale.edu, ycheng@google.com,
ncardwell@google.com
Subject: Re: [PATCH net-next] tcp: tcp_transmit_skb() optimizations
Date: Sat, 12 Oct 2013 01:06:05 -0400 (EDT) [thread overview]
Message-ID: <20131012.010605.1320162777840311015.davem@davemloft.net> (raw)
In-Reply-To: <1381540819.4971.117.camel@edumazet-glaptop.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 11 Oct 2013 18:20:19 -0700
> On Fri, 2013-10-11 at 15:43 -0700, Eric Dumazet wrote:
>> On Fri, 2013-10-11 at 17:48 -0400, David Miller wrote:
>>
>> > This patch is correct, so I've applied it, but it points out a bug.
>> >
>> > The __tcp_retransmit_skb() code that does a __pskb_copy() to handle
>> > NET_IP_ALIGN violations and skb_headroom() overflows is buggy because
>> > it needs to store a congestion control timestamp in the original 'skb'
>> > since that's what we'll look at in the retransmit queue.
>>
>> Yes, I saw that, indeed.
>>
>> I added it as low priority bug for the moment, as the default congestion
>> module do not really care, and this case is really unlikely ;)
>>
>
> Ah, I remember now that the conclusion was :
> the timestamp is not taken into account for retransmits.
>
> ( FLAG_RETRANS_DATA_ACKED )
Great, thanks for the clarification.
prev parent reply other threads:[~2013-10-12 5:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-10 15:43 [PATCH net-next] tcp: tcp_transmit_skb() optimizations Eric Dumazet
2013-10-10 15:54 ` Yuchung Cheng
2013-10-11 21:48 ` David Miller
2013-10-11 22:43 ` Eric Dumazet
2013-10-12 1:20 ` Eric Dumazet
2013-10-12 5:06 ` David Miller [this message]
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