From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Daniel Borkmann <dborkman@redhat.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Florian Westphal <fw@strlen.de>
Subject: Re: High perf top ip_idents_reserve doing netperf UDP_STREAM
Date: Wed, 03 Sep 2014 08:17:06 -0700 [thread overview]
Message-ID: <1409757426.26422.41.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <20140903165943.372b897b@redhat.com>
On Wed, 2014-09-03 at 16:59 +0200, Jesper Dangaard Brouer wrote:
> Hi Eric,
>
> When doing:
> super_netperf 120 -H 192.168.8.2 -t UDP_STREAM -l 100 -- -m 256
>
> I'm seeing function ip_idents_reserve() consuming most CPU. Could you
> help, explain what is going on, and how I can avoid this?
>
> Perf top:
> 11.67% [kernel] [k] ip_idents_reserve
> 8.37% [kernel] [k] fib_table_lookup
> 4.46% [kernel] [k] _raw_spin_lock
> 3.21% [kernel] [k] copy_user_enhanced_fast_string
> 2.92% [kernel] [k] sock_alloc_send_pskb
> 2.88% [kernel] [k] udp_sendmsg
>
Because you use a single destination, all flows compete on a single
atomic to get their next IP identifier.
You can try to use netperf options (-- -N -n) so that netperf uses
connected UDP sockets.
In this case, the IP identifier generator is held in each socket.
next prev parent reply other threads:[~2014-09-03 15:17 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-03 14:59 High perf top ip_idents_reserve doing netperf UDP_STREAM Jesper Dangaard Brouer
2014-09-03 15:17 ` Eric Dumazet [this message]
2016-11-16 12:16 ` Netperf UDP issue with connected sockets Jesper Dangaard Brouer
2016-11-16 17:46 ` Rick Jones
2016-11-16 22:40 ` Jesper Dangaard Brouer
2016-11-16 22:50 ` Rick Jones
2016-11-17 0:34 ` Eric Dumazet
2016-11-17 8:16 ` Jesper Dangaard Brouer
2016-11-17 13:20 ` Eric Dumazet
2016-11-17 13:42 ` Jesper Dangaard Brouer
2016-11-17 14:17 ` Eric Dumazet
2016-11-17 14:57 ` Jesper Dangaard Brouer
2016-11-17 16:21 ` Eric Dumazet
2016-11-17 18:30 ` Jesper Dangaard Brouer
2016-11-17 18:51 ` Eric Dumazet
2016-11-17 21:19 ` Jesper Dangaard Brouer
2016-11-17 21:44 ` Eric Dumazet
2016-11-17 23:08 ` Rick Jones
2016-11-18 0:37 ` Julian Anastasov
2016-11-18 0:42 ` Rick Jones
2016-11-18 17:12 ` Jesper Dangaard Brouer
2016-11-21 16:03 ` Jesper Dangaard Brouer
2016-11-21 18:10 ` Eric Dumazet
2016-11-29 6:58 ` [WIP] net+mlx4: auto doorbell Eric Dumazet
2016-11-30 11:38 ` Jesper Dangaard Brouer
2016-11-30 15:56 ` Eric Dumazet
2016-11-30 19:17 ` Jesper Dangaard Brouer
2016-11-30 19:30 ` Eric Dumazet
2016-11-30 22:30 ` Jesper Dangaard Brouer
2016-11-30 22:40 ` Eric Dumazet
2016-12-01 0:27 ` Eric Dumazet
2016-12-01 1:16 ` Tom Herbert
2016-12-01 2:32 ` Eric Dumazet
2016-12-01 2:50 ` Eric Dumazet
2016-12-02 18:16 ` Eric Dumazet
2016-12-01 5:03 ` Tom Herbert
2016-12-01 19:24 ` Willem de Bruijn
2016-11-30 13:50 ` Saeed Mahameed
2016-11-30 15:44 ` Eric Dumazet
2016-11-30 16:27 ` Saeed Mahameed
2016-11-30 17:28 ` Eric Dumazet
2016-12-01 12:05 ` Jesper Dangaard Brouer
2016-12-01 14:24 ` Eric Dumazet
2016-12-01 16:04 ` Jesper Dangaard Brouer
2016-12-01 17:04 ` Eric Dumazet
2016-12-01 19:17 ` Jesper Dangaard Brouer
2016-12-01 20:11 ` Eric Dumazet
2016-12-01 20:20 ` David Miller
2016-12-01 22:10 ` Eric Dumazet
2016-12-02 14:23 ` Eric Dumazet
2016-12-01 21:32 ` Alexander Duyck
2016-12-01 22:04 ` Eric Dumazet
2016-11-17 17:34 ` Netperf UDP issue with connected sockets David Laight
2016-11-17 22:39 ` Alexander Duyck
2016-11-17 17:42 ` Rick Jones
2016-11-28 18:33 ` Rick Jones
2016-11-28 18:40 ` Rick Jones
2016-11-30 10:43 ` Jesper Dangaard Brouer
2016-11-30 17:42 ` Rick Jones
2016-11-30 18:11 ` David Miller
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