From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Or Gerlitz <gerlitz.or@gmail.com>,
David Miller <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Linux Netdev List <netdev@vger.kernel.org>,
Alexander Duyck <alexander.duyck@gmail.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <borkmann@iogearbox.net>,
Marek Majkowski <marek@cloudflare.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Florian Westphal <fw@strlen.de>, Paolo Abeni <pabeni@redhat.com>,
John Fastabend <john.r.fastabend@intel.com>,
Amir Vadai <amirva@gmail.com>,
brouer@redhat.com
Subject: Re: Optimizing instruction-cache, more packets at each stage
Date: Thu, 21 Jan 2016 13:23:04 +0100 [thread overview]
Message-ID: <20160121132304.12ff9d23@redhat.com> (raw)
In-Reply-To: <CALx6S34H67o64q3YoYiHQ+VSSuSsuSjBXmexSSXF_Hq8fcN0iw@mail.gmail.com>
On Wed, 20 Jan 2016 15:27:38 -0800
Tom Herbert <tom@herbertland.com> wrote:
> weaknesses of Toeplitz we talked about recently and that fact that
> Jenkins is really fast to compute, I am starting to think maybe we
> should always do a software hash and not rely on HW for it...
Please don't enforce a software hash. You are proposing a hash
computation per packet which cost in the area 50-100 nanosec (?). And
on data which is cache cold (even with DDIO, you take the L3 cache
cost/hit).
Consider the increase in network hardware speeds.
Worst-case (pkt size 64 bytes) time between packets:
* 10 Gbit/s -> 67.2 nanosec
* 40 Gbit/s -> 16.8 nanosec
* 100 Gbit/s -> 6.7 nanosec
Adding such a per packet cost is not going to fly.
--
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
next prev parent reply other threads:[~2016-01-21 12:23 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-15 13:22 Optimizing instruction-cache, more packets at each stage Jesper Dangaard Brouer
2016-01-15 13:32 ` Hannes Frederic Sowa
2016-01-15 14:17 ` Jesper Dangaard Brouer
2016-01-15 13:36 ` David Laight
2016-01-15 14:00 ` Jesper Dangaard Brouer
2016-01-15 14:38 ` Felix Fietkau
2016-01-18 11:54 ` Jesper Dangaard Brouer
2016-01-18 17:01 ` Eric Dumazet
2016-01-25 0:08 ` Florian Fainelli
2016-01-15 20:47 ` David Miller
2016-01-18 10:27 ` Jesper Dangaard Brouer
2016-01-18 16:24 ` David Miller
2016-01-20 22:20 ` Or Gerlitz
2016-01-20 23:02 ` Eric Dumazet
2016-01-20 23:27 ` Tom Herbert
2016-01-21 11:27 ` Jesper Dangaard Brouer
2016-01-21 12:49 ` Or Gerlitz
2016-01-21 13:57 ` Jesper Dangaard Brouer
2016-01-21 18:56 ` David Miller
2016-01-21 22:45 ` Or Gerlitz
2016-01-21 22:59 ` David Miller
2016-01-21 16:38 ` Eric Dumazet
2016-01-21 18:54 ` David Miller
2016-01-24 14:28 ` Jesper Dangaard Brouer
2016-01-24 14:44 ` Michael S. Tsirkin
2016-01-24 17:28 ` John Fastabend
2016-01-25 13:15 ` Bypass at packet-page level (Was: Optimizing instruction-cache, more packets at each stage) Jesper Dangaard Brouer
2016-01-25 17:09 ` Tom Herbert
2016-01-25 17:50 ` John Fastabend
2016-01-25 21:32 ` Tom Herbert
2016-01-25 21:58 ` John Fastabend
2016-01-25 22:10 ` Jesper Dangaard Brouer
2016-01-27 20:47 ` Jesper Dangaard Brouer
2016-01-27 21:56 ` Alexei Starovoitov
2016-01-28 9:52 ` Jesper Dangaard Brouer
2016-01-28 12:54 ` Eric Dumazet
2016-01-28 13:25 ` Eric Dumazet
2016-01-28 16:43 ` Tom Herbert
2016-01-28 2:50 ` Tom Herbert
2016-01-28 9:25 ` Jesper Dangaard Brouer
2016-01-28 12:45 ` Eric Dumazet
2016-01-28 16:37 ` Tom Herbert
2016-01-28 16:43 ` Eric Dumazet
2016-01-28 17:04 ` Jesper Dangaard Brouer
2016-01-24 20:09 ` Optimizing instruction-cache, more packets at each stage Tom Herbert
2016-01-24 21:41 ` John Fastabend
2016-01-24 23:50 ` Tom Herbert
2016-01-21 12:23 ` Jesper Dangaard Brouer [this message]
2016-01-21 16:38 ` Tom Herbert
2016-01-21 17:48 ` Eric Dumazet
2016-01-22 12:33 ` Jesper Dangaard Brouer
2016-01-22 14:33 ` Eric Dumazet
2016-01-22 17:07 ` Tom Herbert
2016-01-22 17:17 ` Jesper Dangaard Brouer
2016-02-02 16:13 ` Or Gerlitz
2016-02-02 16:37 ` Eric Dumazet
2016-01-18 16:53 ` Eric Dumazet
2016-01-18 17:36 ` Tom Herbert
2016-01-18 17:49 ` Jesper Dangaard Brouer
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