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From: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
To: Jesper Dangaard Brouer <hawk@diku.dk>
Cc: "Duyck, Alexander H" <alexander.h.duyck@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	netdev <netdev@vger.kernel.org>,
	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@intel.com>,
	"gospo@redhat.com" <gospo@redhat.com>
Subject: Re: [net-next-2.6 PATCH 06/13] igb: move all multicast addresses into multicast table array
Date: Fri, 24 Jul 2009 18:41:29 -0700	[thread overview]
Message-ID: <1248486089.3462.1.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.64.0907241053200.24126@tyr.diku.dk>

On Fri, 2009-07-24 at 01:57 -0700, Jesper Dangaard Brouer wrote:
> On Thu, 23 Jul 2009, Jeff Kirsher wrote:
> 
> > From: Alexander Duyck <alexander.h.duyck@intel.com>
> >
> > This patch moves all of the multicast addresses out of the free Receive
> > address registers and instead programs them all into the multicast table
> > array.  As a result the multicast filtering may not be as precise, but it
> > also greatly reduces the overhead for multicast addresses.
> 
> What do you mean by "the multicast filtering may not be as precise" ?
> 
> I'm planning to use these NICs for multicast traffic (both routing and 
> monitoring).  Is there any precausing I need to be aware of?
> 

The receive address registers, or RARs, are perfect match filters.  The
multicast table array, or MTA, contains hashed values of the multicast
addresses.  Therefore, it isn't a perfect match for the multicast
addresses anymore.  But to support a larger number of multicast
addresses, they can't be written to the RARs, since those resources are
small and are needed for MAC and unicast address filtering.

Cheers,
-PJ Waskiewicz


  reply	other threads:[~2009-07-25  1:42 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-24  4:07 [net-next-2.6 PATCH 01/13] igb: remove media type fiber as it is misleading Jeff Kirsher
2009-07-24  4:07 ` [net-next-2.6 PATCH 02/13] igb: make serdes power down available for 82575 in addition to 82576 parts Jeff Kirsher
2009-07-24  4:07 ` [net-next-2.6 PATCH 03/13] igb: change configure_pcs_link to void since it always returns 0 Jeff Kirsher
2009-07-24  4:08 ` [net-next-2.6 PATCH 04/13] igb: do not overwrite EEPROM LED settings Jeff Kirsher
2009-07-24  4:08 ` [net-next-2.6 PATCH 05/13] igb: add completion timeout workaround for 82575/82576 Jeff Kirsher
2009-07-24  4:08 ` [net-next-2.6 PATCH 06/13] igb: move all multicast addresses into multicast table array Jeff Kirsher
2009-07-24  8:57   ` Jesper Dangaard Brouer
2009-07-25  1:41     ` Peter P Waskiewicz Jr [this message]
2009-07-25 12:45       ` Jesper Dangaard Brouer
2009-07-24  4:09 ` [net-next-2.6 PATCH 07/13] igb: cleanup receive address register initialization Jeff Kirsher
2009-07-24  4:09 ` [net-next-2.6 PATCH 08/13] igb: remove unused switch statement from igb_set_wol Jeff Kirsher
2009-07-24  4:09 ` [net-next-2.6 PATCH 09/13] igb: add support for 82576 mezzanine card Jeff Kirsher
2009-07-24  4:10 ` [net-next-2.6 PATCH 10/13] igb: use buffer_info->dma instead of shinfo->nr_frags to determine unmap Jeff Kirsher
2009-07-24  4:10 ` [net-next-2.6 PATCH 11/13] igb: cleanup flow control configuration to make requested/current more clear Jeff Kirsher
2009-07-24  4:10 ` [net-next-2.6 PATCH 12/13] igb: initialize mailbox function pointers prior to phy init Jeff Kirsher
2009-07-24  4:11 ` [net-next-2.6 PATCH 13/13] igbvf: resolve "frees DMA memory with different size" warnings Jeff Kirsher
2009-07-26 16:47 ` [net-next-2.6 PATCH 01/13] igb: remove media type fiber as it is misleading David Miller

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