On Wed, 11 Jul 2001 14:21:27 -0400 "Michael B. Taylor" <mtaylor@vorticity.engr.utk.edu> wrote: > On Wed, Jul 11, 2001 at 07:04:16PM +0200, Mart van de Wege wrote: > > Folks, > > > > A minor question, possibly OT: for some reason I'm getting a very low > > network throughput between my laptop and my desktop machine. I just > ran a > > test with netpipe-tcp, and the maximum speed is some 15Mbps. As I have > a > > 3Com 905C in the desktop box and a 3Com 574 PCMCIA card on the laptop > > (both are 10/100 NICs) I would have expected a bit more speed here. > Also, > > my laptop complains about dropped interrupts during the test, and a > quick > > look with ifconfig shows that it is having buffer overruns. Is this > > related? Anyone got a clue as to what is going on and how I can boost > my > > network performance? > > > I suspect a driver issue. > > Some NIC's are better supported than others under Linux. Perhaps the > biggest reason for this is the varying degree of support that Linux > recieves different the chipset manufacturers. > > People who need/want/demand near theoretical peak performance from fast > ethernet under linux are usually rather picky about the NIC's they use. > Back in ancient times, when dinosaurs roamed, and there was a company > called > DEC who made a processor called Alpha, the "Tulip" was the chip of > choice. > I really have no idea what the performance champion is wrt stuff you can > actually buy today, but im told that > inexpensive Realtek based cards are perhaps the best bang for the buck. > Aye, I thought of that. That's why I am running 3Com NICs in the first place, as they are *very* well supported, and supposed to give good performance. I've seen benchmarks on the web, done with netpipe as well, that show that they generally are able to saturate the link. > Suggested possible approaches: > > Upgrade your kernel, hence your nic drivers if you are not using a > fairly > current kernel, and keep an eye on release notes of new kernels as they > are released. Hmmm, 2.2.19 on my desktop machine, 2.4.6 on the laptop. should be recent enough, right? > > Or, change your hardware. > See above. I also have a RealTek 8139 on the desktop machine, with the same problem if I try to use that. *If* it is a hardware issue, then it is my poor 3Com 574 on the laptop. > Or, just deal with it. > It is not much of a problem no, but I did not invest a lot of money in good, well supported network hardware to have it run at about 17% of theoretical maximum. It is irritating, to say the least. > Other possabilities: cable issues, router/switch issue Hmmm, it is a straight crosslink UTP-45 cable. I haven't invested in a 3rd PC yet, so no switches here. Question: This is 8 meters of simple crosslink cable. Does the cable length influence perfomance somehow? > Good luck > Mike > Ok, sounds like I need it :) Thanks, Mart -- Baby even the losers get lucky sometimes Even the losers keep a little bit of pride Tom Petty and The Heartbreakers - Even The Losers
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