We are limited to 30 because of the size of the mailbox used for communication from the PF to VF which is only 16 x 32b registers in size, and the first 32b register is reserved for the head. That leaves 15 registers to split into 2 x 16b hashes each.
Too many multicast addresses requested by a VF isn't something we can accommodate because the PF and every VF receive a copy of ANY multicast/broadcast packet received. As a result, performance with multicast and SR-IOV will be very poor with too much multicast address-based traffic. Todd Fujinaka Software Application Engineer Networking Division (ND) Intel Corporation [email protected] (503) 712-4565 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jonathan Purcell Sent: Tuesday, June 10, 2014 8:39 AM To: [email protected]; Linux NICS Subject: [linux-nics] igb/igbvf 30 multicast hash limit. Hi I am trying to understand the impact of the limit of 30 multicast hashes sent from igbvf (e1000_update_mc_addr_list_vf() in e1000_vf.c) to igb (igb_set_vf_multicasts() in igb_main.c). Does this mean that if a system using a VF wants to join more than 30 multicast groups whose low order 12 bits are distinct, in fact it can't? If that is the case is there a way to overcome this? Thanks in advance Jonathan This message is intended only for the stated addressee(s) and may be confidential. Access to this email by anyone else is unauthorised. Any opinions expressed in this email do not necessarily reflect the opinions of Fidessa. Any unauthorised disclosure, use or dissemination, either whole or in part is prohibited. If you are not the intended recipient of this message, please notify the sender immediately. Fidessa plc registered in England and Wales no. 3781700. VAT registration no. GB688900878. Registered office - Dukes Court, Duke Street, Woking, Surrey, GU21 5BH, UK Fidessa buy-side ltd registered in England and Wales no. 3656437. VAT registration no. GB688900878. Registered office - Dukes Court, Duke Street, Woking, Surrey, GU21 5BH, UK Fidessa group plc registered in England and Wales no. 3234176. VAT registration no. GB688900878. Registered office - Dukes Court, Duke Street, Woking, Surrey, GU21 5BH, UK _______________________________________________ Linux-nics mailing list [email protected] ------------------------------------------------------------------------------ HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions Find What Matters Most in Your Big Data with HPCC Systems Open Source. Fast. Scalable. Simple. Ideal for Dirty Data. Leverages Graph Analysis for Fast Processing & Easy Data Exploration http://p.sf.net/sfu/hpccsystems _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
