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Date:   Fri, 22 Apr 2022 13:37:12 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Pengcheng Yang <yangpc@wangsu.com>
Cc:     Eric Dumazet <edumazet@google.com>,
        Neal Cardwell <ncardwell@google.com>, netdev@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net v3] tcp: ensure to use the most recently sent skb
 when filling the rate sample
Message-ID: <20220422133712.17eebbcb@kernel.org>
In-Reply-To: <1650422081-22153-1-git-send-email-yangpc@wangsu.com>
References: <1650422081-22153-1-git-send-email-yangpc@wangsu.com>
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On Wed, 20 Apr 2022 10:34:41 +0800 Pengcheng Yang wrote:
> If an ACK (s)acks multiple skbs, we favor the information
> from the most recently sent skb by choosing the skb with
> the highest prior_delivered count. But in the interval
> between receiving ACKs, we send multiple skbs with the same
> prior_delivered, because the tp->delivered only changes
> when we receive an ACK.
> 
> We used RACK's solution, copying tcp_rack_sent_after() as
> tcp_skb_sent_after() helper to determine "which packet was
> sent last?". Later, we will use tcp_skb_sent_after() instead
> in RACK.
> 
> Fixes: b9f64820fb22 ("tcp: track data delivery rate for a TCP connection")
> Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
> Cc: Neal Cardwell <ncardwell@google.com>
> Cc: Paolo Abeni <pabeni@redhat.com>

Somehow this patch got marked as archived in patchwork. Reviving it now.

Eric, Neal, ack?