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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: brouer@redhat.com,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Alexander Duyck <alexander.h.duyck@intel.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	Daniel Borkmann <dborkman@redhat.com>,
	"Florian Westphal" <fw@strlen.de>,
	"David S. Miller" <davem@davemloft.net>,
	"Stephen Hemminger" <shemminger@vyatta.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Robert Olsson <robert@herjulf.se>,
	Ben Greear <greearb@candelatech.com>,
	John Fastabend <john.r.fastabend@intel.com>,
	"danieltt@kth.se" <danieltt@kth.se>,
	"zhouzhouyi@gmail.com" <zhouzhouyi@gmail.com>
Subject: Re: [net-next PATCH 2/5] ixgbe: increase default TX ring buffer to 1024
Date: Wed, 14 May 2014 21:25:12 +0200	[thread overview]
Message-ID: <20140514212512.196b5136@redhat.com> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1724483B@AcuExch.aculab.com>

On Wed, 14 May 2014 14:28:24 +0000
David Laight <David.Laight@ACULAB.COM> wrote:

> From: Jesper Dangaard Brouer
> > Using pktgen I'm seeing the ixgbe driver "push-back", due TX ring
> > running full.  Thus, the TX ring is artificially limiting pktgen.
> > 
> > Diagnose via "ethtool -S", look for "tx_restart_queue" or "tx_busy"
> > counters.
> 
> Have you tried reducing the tx interrupt mitigation delay.
> It might just be that the end of tx interrupt is delayed too long.

Does the ixgbe have TX interrupt mitigation delays?

I don't "see" them:

$ sudo ethtool -c eth8 
Coalesce parameters for eth8:
Adaptive RX: off  TX: off
stats-block-usecs: 0
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 1
rx-frames: 0
rx-usecs-irq: 0
rx-frames-irq: 0

tx-usecs: 0
tx-frames: 0
tx-usecs-irq: 0
tx-frames-irq: 0

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0


-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Sr. Network Kernel Developer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

  reply	other threads:[~2014-05-14 19:25 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-14 14:17 [net-next PATCH 0/5] Optimizing "pktgen" for single CPU performance Jesper Dangaard Brouer
2014-05-14 14:17 ` [net-next PATCH 1/5] ixgbe: trivial fixes while reading code Jesper Dangaard Brouer
2014-05-14 14:17 ` [net-next PATCH 2/5] ixgbe: increase default TX ring buffer to 1024 Jesper Dangaard Brouer
2014-05-14 14:28   ` David Laight
2014-05-14 19:25     ` Jesper Dangaard Brouer [this message]
2014-05-14 16:28   ` Alexander Duyck
2014-05-14 17:49     ` David Miller
2014-05-14 19:09       ` Jesper Dangaard Brouer
2014-05-14 19:54         ` David Miller
2014-05-15  9:16         ` David Laight
2014-05-29 15:29         ` Jesper Dangaard Brouer
2014-05-14 14:17 ` [net-next PATCH 3/5] pktgen: avoid atomic_inc per packet in xmit loop Jesper Dangaard Brouer
2014-05-14 14:35   ` Eric Dumazet
2014-05-14 15:13     ` Jesper Dangaard Brouer
2014-05-14 15:35       ` Eric Dumazet
2014-05-14 14:17 ` [net-next PATCH 4/5] pktgen: avoid expensive set_current_state() call in loop Jesper Dangaard Brouer
2014-05-14 14:18 ` [net-next PATCH 5/5] pktgen: RCU'ify "if_list" to remove lock in next_to_run() Jesper Dangaard Brouer
2014-06-26 11:16 ` [net-next PATCH V2 0/3] Optimizing pktgen for single CPU performance Jesper Dangaard Brouer
2014-06-26 11:16   ` [net-next PATCH V2 1/3] pktgen: document tuning for max NIC performance Jesper Dangaard Brouer
2014-06-26 11:16   ` [net-next PATCH V2 2/3] pktgen: avoid expensive set_current_state() call in loop Jesper Dangaard Brouer
2014-06-26 11:16   ` [net-next PATCH V2 3/3] pktgen: RCU-ify "if_list" to remove lock in next_to_run() Jesper Dangaard Brouer
2014-07-01 22:51   ` [net-next PATCH V2 0/3] Optimizing pktgen for single CPU performance David Miller

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