From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>,
hannes@stressinduktion.org, netdev@vger.kernel.org,
therbert@google.com, fw@strlen.de, dborkman@redhat.com,
jhs@mojatatu.com, alexander.duyck@gmail.com,
john.r.fastabend@intel.com, dave.taht@gmail.com, toke@toke.dk
Subject: Re: Quota in __qdisc_run()
Date: Tue, 7 Oct 2014 22:07:36 +0200 [thread overview]
Message-ID: <20141007220736.347ad042@redhat.com> (raw)
In-Reply-To: <20141007203700.00e883a1@redhat.com>
On Tue, 7 Oct 2014 20:37:00 +0200
Jesper Dangaard Brouer <brouer@redhat.com> wrote:
> On Tue, 07 Oct 2014 10:32:12 -0700
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
> > On Tue, 2014-10-07 at 13:19 -0400, David Miller wrote:
> >
> > > Yes, this makes sense, do a full qdisc_restart() cycle without boundaries,
> > > then check how much quota was used afterwards to guard the outermost loop.
> >
> > I am testing this, and also am testing the xmit_more patch for I40E.
>
> Check, I'm also testing both yours and Hannes patch.
>
> Results at:
> http://people.netfilter.org/hawk/qdisc/measure18_restore_quota_fairness/
> http://people.netfilter.org/hawk/qdisc/measure19_restore_quota_erics/
> http://people.netfilter.org/hawk/qdisc/measure20_no_quota_baseline_at_git_02c0fc1/
These tests are with ixgbe with a single TXQ, in-order to measure the
effect of HoL, by taking advantage of the high prio queue of pfifo_fast.
(Cmdline trick for a single TXQ: "ethtool -L eth4 combined 1")
In case GSO=off TSO=off, Hannes "wins" with 0.04ms
http://people.netfilter.org/hawk/qdisc/measure19_restore_quota_erics/compare_rr_latency_eric_vs_hannes_NoneXSO.png
which I guess we should not be concerned with.
In case GSO=on TSO=off, the diff is max 0.01ms (to Hannes advantage ;-))
Notice the extreme zoom level:
http://people.netfilter.org/hawk/qdisc/measure19_restore_quota_erics/compare_rr_latency_eric_vs_hannes_GSO.png
In case GSO=on TSO=on, there are some spikes, where Eric's version have
the highest spike.
http://people.netfilter.org/hawk/qdisc/measure19_restore_quota_erics/compare_rr_latency_eric_vs_hannes_TSO.png
Again nothing we should worry about.
Thus, guess we can safely go with Eric's solution, even-thought Hannes
version consistently shows less HoL blocking and less sever spikes, as
the difference is so small. I'm ACKing Eric's version...
We do need this patch, as can be seen by the baseline test at git
commit 02c0fc1. Where some bandwidth unfairness to the UDP flows
happens, but only in the case GSO=off TSO=off (others are fine).
http://people.netfilter.org/hawk/qdisc/measure20_no_quota_baseline_at_git_02c0fc1/NoneXSO_10Gbit_base_02c0fc1_bandwidth_totals_unfairness.png
Kind of strange, but it went away in the two quota tests.
--
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
next prev parent reply other threads:[~2014-10-07 20:08 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-01 20:35 [net-next PATCH V6 0/2] qdisc: bulk dequeue support Jesper Dangaard Brouer
2014-10-01 20:35 ` [net-next PATCH V6 1/2] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE Jesper Dangaard Brouer
2014-10-01 20:36 ` [net-next PATCH V6 2/2] qdisc: dequeue bulking also pickup GSO/TSO packets Jesper Dangaard Brouer
2014-10-02 14:35 ` Eric Dumazet
2014-10-02 14:38 ` Daniel Borkmann
2014-10-02 14:42 ` [net-next PATCH V6 0/2] qdisc: bulk dequeue support Tom Herbert
2014-10-02 15:04 ` Eric Dumazet
2014-10-02 15:24 ` [PATCH net-next] mlx4: add a new xmit_more counter Eric Dumazet
2014-10-05 0:04 ` David Miller
2014-10-02 15:27 ` [net-next PATCH V6 0/2] qdisc: bulk dequeue support Tom Herbert
2014-10-02 16:52 ` Florian Westphal
2014-10-02 17:32 ` Eric Dumazet
2014-10-02 17:35 ` Tom Herbert
2014-10-03 19:38 ` David Miller
2014-10-03 20:57 ` Eric Dumazet
2014-10-03 21:56 ` David Miller
2014-10-03 21:57 ` Eric Dumazet
2014-10-03 22:15 ` Eric Dumazet
2014-10-03 22:19 ` Tom Herbert
2014-10-03 22:56 ` Eric Dumazet
2014-10-03 22:30 ` David Miller
2014-10-03 22:31 ` [PATCH net-next] qdisc: validate skb without holding lock Eric Dumazet
2014-10-03 22:36 ` David Miller
2014-10-03 23:30 ` Eric Dumazet
2014-10-07 7:34 ` Quota in __qdisc_run() (was: qdisc: validate skb without holding lock) Jesper Dangaard Brouer
2014-10-07 12:47 ` Eric Dumazet
2014-10-07 13:30 ` Jesper Dangaard Brouer
2014-10-07 14:43 ` Hannes Frederic Sowa
2014-10-07 15:01 ` Eric Dumazet
2014-10-07 15:06 ` Eric Dumazet
2014-10-07 17:19 ` Quota in __qdisc_run() David Miller
2014-10-07 17:32 ` Eric Dumazet
2014-10-07 18:37 ` Jesper Dangaard Brouer
2014-10-07 20:07 ` Jesper Dangaard Brouer [this message]
2014-10-07 18:03 ` Jesper Dangaard Brouer
2014-10-07 19:10 ` Eric Dumazet
2014-10-07 19:34 ` Jesper Dangaard Brouer
2014-10-07 15:26 ` Quota in __qdisc_run() (was: qdisc: validate skb without holding lock) Jesper Dangaard Brouer
2014-10-08 17:38 ` Quota in __qdisc_run() John Fastabend
2014-10-06 14:12 ` [PATCH net-next] qdisc: validate skb without holding lock Jesper Dangaard Brouer
2014-10-04 3:59 ` [PATCH net-next] net: skb_segment() provides list head and tail Eric Dumazet
2014-10-06 4:38 ` David Miller
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