Subject: Re: link0 and ifconfig
To: Mipam <mipam@ibb.net>
From: Lubomir Sedlacik <salo@Xtrmntr.org>
List: netbsd-users
Date: 08/09/2004 12:32:43
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hi,

On Mon, Aug 09, 2004 at 11:49:37AM +0200, Mipam wrote:
>=20
> > man ifconfig, search for link[0-2]:
>=20
> Thanks for your answer.  I was actually searching for something else.
> When you have a machine with need to digest high loads of network
> traffic, the cpu is also loaded more to process the packets.  Checksum
> offloading helps to save cpu cycles, but maybe a bigger bottleneck may
> be the amount of interrupts that are being generated.  Normally for
> each packet that is received, an interrupt is triggered.  I was
> looking for IRQ mitigation to remedy this somewhat, so that these
> interrupts are being surpressed until the nics FIFO is full. This
> saves the amount of interrupts and thus saves cpu cycles.  Some cards
> may support this feature, some intel cards do.  Is their support for
> this feature?  Or are there other ways to reduce the amount of
> interrupts.  FreeBSD also supports device polling to get ridd of
> interrupt stuff, this works with some cards. I was wondering what i
> can do reduce it?

fxp(4)

     Certain versions of the i8255x support loading microcode which
implements a receive interrupt mitigation function, known as
``CPUSaver''.  Use of this option can improve performance in some
situations by reducing interrupt load on the host.  This option is
available on the following chip versions:

     o   i82558 step A4 (rev 4)
     o   i82558 step B0 (rev 5)
     o   i82559 step A0 (rev 8)
     o   i82559S step A (rev 9)
     o   i82550 (rev 12)
     o   i82550 step C (rev 13)

     This option is enabled by setting the ``link0'' option with
ifconfig(8).


regards,

--=20
-- Lubomir Sedlacik <salo@{NetBSD,Xtrmntr,silcnet}.org>   --

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