From owner-freebsd-net@freebsd.org  Mon Aug 17 11:54:08 2015
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Date: Mon, 17 Aug 2015 14:54:05 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Alban Hertroys <haramrae@gmail.com>
Cc: Daniel Braniss <danny@cs.huji.ac.il>,
 FreeBSD Net <freebsd-net@freebsd.org>,
 FreeBSD stable <freebsd-stable@freebsd.org>
Subject: Re: ix(intel) vs mlxen(mellanox) 10Gb performance
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On Mon, Aug 17, 2015 at 01:49:27PM +0200, Alban Hertroys wrote:

> On 17 August 2015 at 13:39, Slawa Olhovchenkov <slw@zxy.spb.ru> wrote:
> 
> > In any case, for 10Gb expect about 1200MGB/s.
> 
> Your usage of units is confusing. Above you claim you expect 1200

I am use as topic starter and expect MeGaBytes per second

> million gigabytes per second, or 1.2 * 10^18 Bytes/s. I don't think
> any known network interface can do that, including highly experimental
> ones.
> 
> I suspect you intended to claim that you expect 1.2GB/s (Gigabytes per
> second) over that 10Gb/s (Gigabits per second) network.
> That's still on the high side of what's possible. On TCP/IP there is
> some TCP overhead, so 1.0 GB/s is probably more realistic.

TCP give 5-7% overhead (include retrasmits).
10^9/8*0.97 = 1.2125