From: Neal Cardwell <ncardwell@google.com>
To: Yuchung Cheng <ycheng@google.com>
Cc: davem@davemloft.net, ilpo.jarvinen@helsinki.fi,
nanditad@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH v3 3/3] tcp: early retransmit: delayed fast retransmit
Date: Wed, 2 May 2012 15:34:41 -0400 [thread overview]
Message-ID: <CADVnQyn6K8xH=wwi7pN0wsKS4wEhksi2pB0KbTaSDqLGWmnBaw@mail.gmail.com> (raw)
In-Reply-To: <1335984391-31340-3-git-send-email-ycheng@google.com>
On Wed, May 2, 2012 at 2:46 PM, Yuchung Cheng <ycheng@google.com> wrote:
> Implementing the advanced early retransmit (sysctl_tcp_early_retrans==2).
> Delays the fast retransmit by an interval of RTT/4. We borrow the
> RTO timer to implement the delay. If we receive another ACK or send
> a new packet, the timer is cancelled and restored to original RTO
> value offset by time elapsed. When the delayed-ER timer fires,
> we enter fast recovery and perform fast retransmit.
>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> ---
> ChangeLog in v2:
> - Set sysctl_tcp_early_retrans default to 2
> ChangeLog in v3:
> - use separate u8 for early retrans stats in tcp_sock
> - disable ER if detects any reordering
After reading patch 3 of the series, I see that patch 3 incorporates
most of those suggestions from Monday. I think it would be quite a bit
cleaner to just have patch 2 of the series put the
tcp_disable_early_retrans() call and tcp_sock fields in the ultimately
desired place, rather than having patch 2 put them somewhere and patch
3 move them, but maybe that's just me.
When all the patches in the series are applied, the one issue I still
see is that frto_counter is in a new place, a bit further away from
frto_highmark than it used to be before the patch series. I think it
would be good to keep frto_counter in its original location, back up
nearer to frto_highmark.
neal
next prev parent reply other threads:[~2012-05-02 19:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 18:46 [PATCH v3 1/3] tcp: early retransmit: tcp_enter_recovery() Yuchung Cheng
2012-05-02 18:46 ` [PATCH v3 2/3] tcp: early retransmit Yuchung Cheng
2012-05-02 19:14 ` Neal Cardwell
2012-05-02 18:46 ` [PATCH v3 3/3] tcp: early retransmit: delayed fast retransmit Yuchung Cheng
2012-05-02 19:34 ` Neal Cardwell [this message]
2012-05-02 21:17 ` Yuchung Cheng
2012-05-02 18:49 ` [PATCH v3 1/3] tcp: early retransmit: tcp_enter_recovery() Eric Dumazet
2012-05-02 19:03 ` Neal Cardwell
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