From: Martin KaFai Lau <kafai@fb.com>
To: Soheil Hassas Yeganeh <soheil@google.com>
Cc: netdev <netdev@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Neal Cardwell <ncardwell@google.com>,
Willem de Bruijn <willemb@google.com>,
Yuchung Cheng <ycheng@google.com>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [RFC PATCH v3 net-next 2/3] tcp: Handle eor bit when coalescing skb
Date: Thu, 21 Apr 2016 09:56:33 -0700 [thread overview]
Message-ID: <20160421165633.GA74969@kafai-mba.local> (raw)
In-Reply-To: <CACSApvbyD7wFy+y2MrShKRMCTg-zF6UkP-Le867N=ssCYa-Yng@mail.gmail.com>
On Wed, Apr 20, 2016 at 04:04:54PM -0400, Soheil Hassas Yeganeh wrote:
> > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> > index a6e4a83..96bdf98 100644
> > --- a/net/ipv4/tcp_output.c
> > +++ b/net/ipv4/tcp_output.c
> > @@ -2494,6 +2494,7 @@ static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb)
> > * packet counting does not break.
> > */
> > TCP_SKB_CB(skb)->sacked |= TCP_SKB_CB(next_skb)->sacked & TCPCB_EVER_RETRANS;
> > + TCP_SKB_CB(skb)->eor = TCP_SKB_CB(next_skb)->eor;
> >
> > /* changed transmit queue under us so clear hints */
> > tcp_clear_retrans_hints_partial(tp);
> > @@ -2545,6 +2546,9 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *to,
> > if (!tcp_can_collapse(sk, skb))
> > break;
> >
> > + if (TCP_SKB_CB(to)->eor)
> > + break;
> > +
>
> nit: Perhaps a better place to check for eor is right after entering
> the loop? to skip a few instructions and tcp_can_collapse, in an
> unlikely case eor is set.
hmm... Not sure I understand it.
You meant moving the unlikely case before (or after?) the more likely
cases which may have a better chance to break the loop sooner?
next prev parent reply other threads:[~2016-04-21 16:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-20 6:24 [RFC PATCH v3 net-next 0/3] tcp: Make use of MSG_EOR in tcp_sendmsg Martin KaFai Lau
2016-04-20 6:24 ` [RFC PATCH v3 net-next 1/3] tcp: Make use of MSG_EOR in tcp_sendmsg and tcp_sendpage Martin KaFai Lau
2016-04-20 9:21 ` Eric Dumazet
2016-04-20 6:24 ` [RFC PATCH v3 net-next 2/3] tcp: Handle eor bit when coalescing skb Martin KaFai Lau
2016-04-20 20:04 ` Soheil Hassas Yeganeh
2016-04-21 16:56 ` Martin KaFai Lau [this message]
2016-04-21 21:14 ` Soheil Hassas Yeganeh
2016-04-22 4:30 ` Martin KaFai Lau
2016-04-20 6:24 ` [RFC PATCH v3 net-next 3/3] tcp: Handle eor bit when fragmenting a skb Martin KaFai Lau
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