Re: Can't reach the Gigabit barrier
On Thu, Apr 14, 2005 at 04:13:42AM -0700, Steve Ramage wrote:
> mii-tools says that I'm running at 100 Mbps, but the man pages say that
> it doesn't support 1000 Mbps (well actually it says it only supports...
> and 1000 Mbps isn't there).
I thought mii-tool was depricated. Stick with ethtool.
> Furthermore ethtool seems to be just as useless as its information seems
> to be completely irrelevant. For instance if I use ethtool to change the
> speed, it doesn't. If I tell mii-tool to change it to 10 Mbps, it does
> change it, but ethtool still says the linkspeed is 1000 Mbps.
If you're using gigE, there's no support in the standard for forcing
the setting. You need to set the NIC to autoneg with ethtool, or else
you may be setting it lower and confusing your dumb switch because it
won't know about how to handle ports that are set to anything but autoneg.
> Someone had suggested it might be the cable, but its not for a few
> reasons. One the windows box has a Cat5 not Cat5e/6 cable and I manage
> to crack 100 Mbps, and secondly, I dug up a Cat5e and it has had no effect.
Stick with the best cabling you can find. You're in a bind because if
your switch is unmanaged you can't tell if the switch is seeing
dropped packets or any other problem.
> I have also tried passing parameters to the e1000 module directly, but
> still no luck. Anyone have any ideas? (This is debian-testing, btw)
Try using autoneg, and try using an application that can actually
stream tcp because otherwise the overhead of context switching
something even as simple as ping is going to screw your numbers
because ping is not a speed demon.
Since you have two systems, why not use netperf?
-Peter
--
The 5 year plan:
In five years we'll make up another plan.
Or just re-use this one.
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