Date: Sat, 29 Sep 2001 17:02:58 -0700 (PDT) From: wpaul@FreeBSD.ORG (Bill Paul) To: ken@kdm.org (Kenneth D. Merry) Cc: jlemon@flugsvamp.com, the_srinivas@hotmail.com, hackers@FreeBSD.ORG Subject: Re: TCP&IP cksum offload on FreeBSD 4.2 Message-ID: <20010930000258.B7EEF37B403@hub.freebsd.org> In-Reply-To: <20010929153932.A50715@panzer.kdm.org> from "Kenneth D. Merry" at "Sep 29, 2001 03:39:32 pm"
next in thread | previous in thread | raw e-mail | index | archive | help
> > On the other hand, the Tigon III > > is capable of 960 megabits -- about the wire rate limit -- > > with normal size packets, if you implement software interrupt > > coelescing (which doesn't help, unless you crank the load up > > to close to wire speed and/or do more of the stack processing > > at interrupt time). I've been able to get 906Mbps between two Dell PowerEdge 2550 servers with built-in BCM5700/Tigon III chipsets with a stock FreeBSD kernel and the bge driver. > Having downloadable firmware is actually a huge advantage. You can do > things with the Tigon II that just aren't possible with any other chip, > either because they don't have downloadable firmware, or because the vendor > won't release firmware source. > > This is a problem with the Broadcom Tigon III boards, and to some extent > with the Tigon II. Basically it looks like the firmware for the Tigon II > is very hard to get now that 3Com has control of it, and I don't think > Broadcom will release the Tigon III firmware. (Assuming it is a > firmware-based chip.) I still have a copy of the last release of the Tigon II firmware and the development environment (which is what I used to generate the firmware image included with FreeBSD). As for the Tigon III, there is a default firmware image included in the EEPROM on the card, which is auto-loaded when the chip powers up. It is possible for a driver to load a custom image into the NIC's memory which will override the auto-loaded one, and it's also possible to load a new image into the EEPROM, however this requires an additional manual on top of the BCM5700 driver developer's guide as well as the firmware development kit, which you can only get from Broadcom/3Com/whatever under NDA. These custom images are called "value-add" firmware which are used to provide features like TCP segmentation, which you can't do with the default firmware image. Note that the BCM5700/Tigon III only has a limited amount of on-board RAM (256KB, I think). You're supposed to be able to attach up to 16MB of static SRAM to the BCM5700. The BCM5701 doesn't support external SSRAM at all, which I find a little confusing. -Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010930000258.B7EEF37B403>