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: Fri, 11 Oct 2013 17:48:58 -0400 (EDT) [thread overview]
Message-ID: <20131011.174858.1461090000704613432.davem@davemloft.net> (raw)
In-Reply-To: <1381419780.4971.84.camel@edumazet-glaptop.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 10 Oct 2013 08:43:00 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> 1) We need to take a timestamp only for skb that should be cloned.
>
> Other skbs are not in write queue and no rtt estimation is done on them.
>
> 2) the unlikely() hint is wrong for receivers (they send pure ACK)
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
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.
next prev parent reply other threads:[~2013-10-11 21:49 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 [this message]
2013-10-11 22:43 ` Eric Dumazet
2013-10-12 1:20 ` Eric Dumazet
2013-10-12 5:06 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20131011.174858.1461090000704613432.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=eric.dumazet@gmail.com \
--cc=fitz@cs.yale.edu \
--cc=ncardwell@google.com \
--cc=netdev@vger.kernel.org \
--cc=ycheng@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).