Date: Mon, 14 Mar 2011 21:40:36 -0700 From: Vijay Singh <vijju.singh@gmail.com> To: pyunyh@gmail.com Cc: freebsd-net@freebsd.org Subject: Re: Jumbo frame support for BGE_ASICREV_BCM5714 Message-ID: <AANLkTi=brPL3Krre%2BvYe-P4jvPu3=rQ%2Be-EHjTB%2Bbb=4@mail.gmail.com> In-Reply-To: <20110315024325.GG1577@michelle.cdnetworks.com> References: <AANLkTimqca%2B72jvWi89LnrP0F4MNdvK7YaG2pTavNiC3@mail.gmail.com> <20110315024325.GG1577@michelle.cdnetworks.com>
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> As you know, BCM5714, BCM5715 and BCM5780 use unique jumbo frame > scheme that is not compatible with other controllers. All other > Broadcom controllers have better jumbo frame scheme. These > controllers have one send ring, one standard receive producer ring > and one receive return ring. In order to receive jumbo frames on > these controllers you have to increase Rx buffer size to hold 9k > sized jumbo frame. Two Rx modes(standard Rx BDs and extended Rx > BDs) are supported for these controllers. Using extended Rx BDs on > BCM5714/BCM5715/BCM5780 reduces the number of Rx BDs to 256 entries > which shall reduce the performance. I would use standard Rx BDs to > hold 512 entries for RX buffers. > > I think I received jumbo frame support request for these > controllers in past. At that time I had no interests on > implementing it due to severe implementation differences. What is > your main reason to use jumbo frame on this controller? What is > your expectation on performance numbers? I guess no other OSes > support jumbo frame on this controller. Hi Pyun, I am stuck with this NIC due to it being the one present in the HW platform that I have to support. The performance is expectation is mainly for apps that use large payloads (where something TSO would have helped). -vijay
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