From: Jesper Dangaard Brouer <brouer@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org,
therbert@google.com, hannes@stressinduktion.org, 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,
brouer@redhat.com
Subject: Re: [PATCH net-next] qdisc: validate skb without holding lock
Date: Mon, 6 Oct 2014 16:12:35 +0200 [thread overview]
Message-ID: <20141006161235.010033f5@redhat.com> (raw)
In-Reply-To: <20141003.153645.72976986956341944.davem@davemloft.net>
On Fri, 03 Oct 2014 15:36:45 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Fri, 03 Oct 2014 15:31:07 -0700
>
> > From: Eric Dumazet <edumazet@google.com>
> >
> > Validation of skb can be pretty expensive :
> >
> > GSO segmentation and/or checksum computations.
> >
> > We can do this without holding qdisc lock, so that other cpus
> > can queue additional packets.
> >
[...]
> >
> > Turning TSO on or off had no effect on throughput, only few more cpu
> > cycles. Lock contention on qdisc lock disappeared.
This is good work! Lock contention significantly reduced!
My 10G tests just 2x 10G netperf TCP_STREAM shows:
With GSO=off TSO=off, _raw_spin_lock is now only at perf top#13 with
1.44% (80% from qdisc calls, 60% is from __dev_queue_xmit and 20% from
sch_direct_xmit) (before with qdisc bulking is was 2.66%).
The "show off" case is GSO=on TSO=off, where raw_spin_lock is now only
at perf top#26 with 0.85% and only 54.74% comes from qdisc calls
(52.07% sch_direct_xmit and 2.67% __dev_queue_xmit).
This is some significant improvements to the kernels xmit layer,
me very happy!!! :-))) Thanks everyone!
--
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:[~2014-10-06 14:13 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
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 ` Jesper Dangaard Brouer [this message]
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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