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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Tom Herbert <tom@herbertland.com>
Cc: brouer@redhat.com, <davem@davemloft.net>,
	<netdev@vger.kernel.org>, <rick.jones2@hpe.com>,
	<kernel-team@fb.com>, Achiad Shochat <achiad@mellanox.com>
Subject: Re: [PATCH RFC 2/4] bql: Add tracking of inflight packets
Date: Wed, 31 Aug 2016 11:23:33 +0200	[thread overview]
Message-ID: <20160831112333.5be19dbe@redhat.com> (raw)
In-Reply-To: <1472601634-531498-3-git-send-email-tom@herbertland.com>

On Tue, 30 Aug 2016 17:00:32 -0700
Tom Herbert <tom@herbertland.com> wrote:

> Add two fields to netdev_queue as head_cnt and tail_cnt. head_cnt is
> incremented for every sent packet in netdev_tx_sent_queue and tail_cnt
> is incremented by the number of packets in netdev_tx_completed_queue.
> So then the number of inflight packets for a queue is simply
> queue->head_cnt - queue->tail_cnt.
> 
> Add inflight_pkts to be reported in sys-fs.

I like the idea of BQL tracking inflight packets, because we could use this
to determine _when_ qdisc bulking could be beneficial (activating xmit_more).

Idea from NetDev1.1 slides[1] page 17, and experiment with BQL
byte_queue_limits/limit_max on page 18 (which would really need a pkt
count not a byte count)

[1] http://people.netfilter.org/hawk/presentations/NetDev1.1_2016/net_performance_BoF.pdf
[2] http://people.netfilter.org/hawk/presentations/NetDev1.1_2016/links.html
-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

  reply	other threads:[~2016-08-31  9:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-31  0:00 [PATCH RFC 0/4] xfs: Transmit flow steering Tom Herbert
2016-08-31  0:00 ` [PATCH RFC 1/4] net: Set SW hash in skb_set_hash_from_sk Tom Herbert
2016-08-31  0:00 ` [PATCH RFC 2/4] bql: Add tracking of inflight packets Tom Herbert
2016-08-31  9:23   ` Jesper Dangaard Brouer [this message]
2016-08-31 13:08   ` Eric Dumazet
2016-08-31  0:00 ` [PATCH RFC 3/4] net: Add xps_dev_flow_table_cnt Tom Herbert
2016-08-31  0:00 ` [PATCH RFC 4/4] xfs: Transmit flow steering Tom Herbert
2016-08-31  3:14   ` Alexander Duyck
2016-08-31 18:34   ` Chris Mason
2016-09-28 15:13 ` [PATCH RFC 0/4] " Rick Jones
2016-10-07  9:18   ` Juerg Haefliger

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