On Fri, Dec 03, 2004 at 10:09:23AM -0500, TJ wrote: > I did not know that auto-sensing was part of the Gigabit standard. I don't > understand why you would think that performance would be worse with a > crossover than a straight cable, though. I assure you, the link > autonegotiates to a gigabit connection. The card driver reports this, the > card's light indicator reports this, and my benchmarking of throughput has > proven it. That means you have a crossover cable with two wire pairs crossed and two wire pairs straight, and guess what: gigE automatically detects badly wired cables (to a certain extent), correct it and negotiate to the correct speed: 1 Gbit/s. If you have a crossover cable using only two crossed wire pairs and the other pairs not connected, the link will negotiate to 100 Mbit/s. > > The Intel gigE NICs are very good: good hardware, good driver, good > > support. Gigabit ethernet switches are becoming rather cheap: 200 EUR > > buys you an 8 port switch. > > Yeah, I knew Intel made good NIC's, and I knew they were linux supported. I'm > only worried because this is the lowest end model in the line. I wonder if it > offloads work to the CPU, causing lower throughput on a busy link, while more > expensive versions handle more work on the card. We use the dual ported PCI-X server adapters in the file servers (dual Athlon and dual Opteron), but to be honest I haven't seen a difference in performance with the desktop adapters when we replaced them. It's just that they're 64 bit wide and have two NICs on a single board (and hence only use one PCI slot). The other machines (about 10 or so) have the cheaper desktop adapters. > Also, I have read some traffic that the e1000 driver is better tuned > for light duty connections, and could use some improvement under a > heavy workload. If you knew about any documentation, or mailing lists > on the topic of tuning this, I'd appreciate it. I can't comment on that. We push several gigabytes/day through the cards and I haven't seen any real problems. We had performance problems with NatSemi gigE NICs; Broadcom gigE NICs looks like too much driver hassle to me (judging from posts on linux-kernel). Documentation can be found on http://sourceforge.net/projects/e1000 , the appropriate mailing list is the networking list: netdev@xxxxxxxxxxx . Erik -- +-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 -- | Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands | Data lost? Stay calm and contact Harddisk-recovery.com - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
