From: David Miller <davem@davemloft.net>
To: edumazet@google.com
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, soheil@google.com
Subject: Re: [PATCH net-next] tcp: batch calls to sk_flush_backlog()
Date: Fri, 09 Aug 2019 11:07:05 -0700 (PDT) [thread overview]
Message-ID: <20190809.110705.591778512450074017.davem@davemloft.net> (raw)
In-Reply-To: <20190809120447.93591-1-edumazet@google.com>
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 9 Aug 2019 05:04:47 -0700
> Starting from commit d41a69f1d390 ("tcp: make tcp_sendmsg() aware of socket backlog")
> loopback flows got hurt, because for each skb sent, the socket receives an
> immediate ACK and sk_flush_backlog() causes extra work.
>
> Intent was to not let the backlog grow too much, but we went a bit too far.
>
> We can check the backlog every 16 skbs (about 1MB chunks)
> to increase TCP over loopback performance by about 15 %
>
> Note that the call to sk_flush_backlog() handles a single ACK,
> thanks to coalescing done on backlog, but cleans the 16 skbs
> found in rtx rb-tree.
>
> Reported-by: Soheil Hassas Yeganeh <soheil@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied.
prev parent reply other threads:[~2019-08-09 18:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 12:04 [PATCH net-next] tcp: batch calls to sk_flush_backlog() Eric Dumazet
2019-08-09 13:08 ` Soheil Hassas Yeganeh
2019-08-09 18:07 ` David Miller [this message]
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