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Date:      Thu, 27 Jan 2011 13:44:14 -0800
From:      Jack Vogel <jfvogel@gmail.com>
To:        Jeremy Chadwick <freebsd@jdc.parodius.com>
Cc:        Sergey Lobanov <wmn@siberianet.ru>, "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org>, "freebsd-pf@freebsd.org" <freebsd-pf@freebsd.org>
Subject:   Re: High interrupt rate on a PF box + performance
Message-ID:  <AANLkTi=JYFNkXBGdmrt%2B0pq4PJZS=9gG-iV1OMOSkew3@mail.gmail.com>
In-Reply-To: <20110127205845.GA41537@icarus.home.lan>
References:  <4D41417A.20904@my.gd> <1DB50624F8348F48840F2E2CF6040A9D014BEB8833@orsmsx508.amr.corp.intel.com> <4D41B197.6070308@my.gd> <201101280146.57028.wmn@siberianet.ru> <4D41C9FC.10503@my.gd> <20110127195741.GA40449@icarus.home.lan> <4D41D7BE.3030208@my.gd> <20110127205845.GA41537@icarus.home.lan>

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On Thu, Jan 27, 2011 at 12:58 PM, Jeremy Chadwick
<freebsd@jdc.parodius.com>wrote:

>
> On Thu, Jan 27, 2011 at 09:38:22PM +0100, Damien Fleuriot wrote:
> > On 1/27/11 8:57 PM, Jeremy Chadwick wrote:
> >
>
> <...snipping out stuff...>
>
> > We're also considering moving to faster machines but I don't think that
> > will help much with our problem.
> >
> > I suppose additional CPU cores will be of no help at all, considering
> > the kernel is single threaded and runs on cpu0 only ?
>
> Kernel folks should be able to talk about this in detail, but my
> understanding is that the kernel itself supports multiple threads, but
> the question is whether or not the drivers or relevant "pieces" (e.g.
> igb(4) driver, pf, TCP stack, etc.) support SMP (multi-core/threading)
> or not.  I think this is referred to as something being "MPSAFE" or not.
>
>
The 8.X kernel is NOT single-threaded. Anything but. And the stack has
also been improved, I believe there are still bottlenecks but its far better
than the old days.

The igb driver in 8.2 creates up to 8 queues on the right hardware, they
are each auto-bound to a particular CPU.

The older version you are running had issues and hence multiqueue was
not enabled.  So, do upgrade once 8.2 is finalized :)

Cheers,

Jack



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