From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: Re: [PATCH] NET: Multiqueue network device support. Date: Tue, 12 Jun 2007 14:52:11 -0700 Message-ID: References: <20070612.140240.00078635.davem@davemloft.net> <466F0C92.5080306@garzik.org> <466F0D78.7090404@candelatech.com> <20070612.142658.45082832.davem@davemloft.net> <466F142C.4040109@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , greearb@candelatech.com, netdev@vger.kernel.org, kaber@trash.net, hadi@cyberus.ca, peter.p.waskiewicz.jr@intel.com, auke-jan.h.kok@intel.com To: Jeff Garzik Return-path: Received: from sj-iport-6.cisco.com ([171.71.176.117]:22531 "EHLO sj-iport-6.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954AbXFLVwT (ORCPT ); Tue, 12 Jun 2007 17:52:19 -0400 In-Reply-To: <466F142C.4040109@garzik.org> (Jeff Garzik's message of "Tue, 12 Jun 2007 17:46:20 -0400") Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > > The MAC is still very much centralized in most designs. > > So one way they'll do it is to support assigning N MAC addresses, > > and you configure the input filters of the chip to push packets > > for each MAC to the proper receive queue. > > So the MAC will accept any of those in the N MAC addresses as > > it's own, then you use the filtering facilities to steer > > frames to the correct RX queue. > > Not quite... You'll have to deal with multiple Rx filters, not just > the current one-filter-for-all model present in today's NICs. Pools > of queues will have separate configured characteristics. The "steer" > portion you mention is a bottleneck that wants to be eliminated. I think you're misunderstanding. These NICs still have only one physical port, so sending or receiving real packets onto a physical wire is fundamentally serialized. The steering of packets to receive queues is done right after the packets are received from the wire -- in fact it can be done as soon as the NIC has parsed enough of the headers to make a decision, which might be before the full packet has even been received. The steering is no more of a bottleneck than the physical link is. - R.