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Date: Fri, 24 Jul 2015 10:50:10 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Xin Li <delphij@delphij.net>
Cc: d@delphij.net, re@FreeBSD.org, freebsd-stable@freebsd.org
Subject: Re: freebsd downgrade
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On Fri, Jul 24, 2015 at 12:43:11AM -0700, Xin Li wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA512
> 
> 
> 
> On 7/24/15 00:20, Slawa Olhovchenkov wrote:
> > On Thu, Jul 23, 2015 at 04:51:07PM -0700, Xin Li wrote:
> > 
> >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512
> >> 
> >> On 07/23/15 16:21, Stari Karp wrote:
> >>> Hi!
> >>> 
> >>> I had a problems with FreeBSD 10.2-BETA2. I used
> >>> freebsd-update ugrade and update FreeBSD 10.1-RELEASE. Is it
> >>> possible to downgrade BETA2 to 10.1-RELEASE with freebsd-update
> >>> upgrade -r 10.1-RELEASE, please?
> >> 
> >> It's not supported (because you may be running binaries that
> >> depends on new kernel).
> >> 
> >> What kind of problems did you have?  Please let re@ know so we
> >> can get them fixed.
> > 
> > For me -- degradate network performance, about 30%. I am do
> > verification now, by downgrading kernel.
> 
> What kind of workload and what NIC are you using?

Chelsio T580-LP-CR, http serving.
r276179 can utilise 40Gbit, r281264 -- only 28Gbit.