From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: ncardwell@google.com, ycheng@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] tcp: implement TSQ for retransmits
Date: Thu, 22 Sep 2016 02:44:54 -0400 (EDT) [thread overview]
Message-ID: <20160922.024454.403661058785255364.davem@davemloft.net> (raw)
In-Reply-To: <1474436758.23058.75.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 20 Sep 2016 22:45:58 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> We saw sch_fq drops caused by the per flow limit of 100 packets and TCP
> when dealing with large cwnd and bursts of retransmits.
>
> Even after increasing the limit to 1000, and even after commit
> 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time"),
> we can still have these drops.
>
> Under certain conditions, TCP can spend a considerable amount of
> time queuing thousands of skbs in a single tcp_xmit_retransmit_queue()
> invocation, incurring latency spikes and stalls of other softirq
> handlers.
>
> This patch implements TSQ for retransmits, limiting number of packets
> and giving more chance for scheduling packets in both ways.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
Applied.
prev parent reply other threads:[~2016-09-22 6:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1474424880.23058.65.camel@edumazet-glaptop3.roam.corp.google.com>
2016-09-21 5:45 ` [PATCH net-next] tcp: implement TSQ for retransmits Eric Dumazet
2016-09-22 6:44 ` David Miller [this message]
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