Re: [gentoo-user] 1000Mbps NIC Getting 100Mbps speeds

[Sascha Lucas]

Right, everything except mii-tool (which apparently can't understand
1000Mbps) says 1000Mbps.
ok. what I want to say is that mii-tool is knowen to report the wrong 
speed for all/some Gbit cards (just for the case of missunderstanding).

Your setup seems to be fine. It's worth to try ping (floodping with 
increasing packet size):

$ ping -f -s $SIZE target
SIZE is default 56. SIZE=1480 comes close to MTU and 65507 is the biggest 
possible size.

You can messure the bandwidth with iptraf/iftop on the linux-side. With a 
small SIZE you get your max. packets/sec (iptraf) but with increasing SIZE 
bits/sec should also increase.

ping -f should have no (increasing) packet lose (see man ping).
Right. I'm familiar with speeds too. When it was connected an FTP
session would get about 9MB/s then slow to 8 or so, then stay there.
This is exactly the behavior i'm seeing now.
The bandwidth depends on the networkcard you are using and the CPU you 
have. Take a look on both sides CPUs. Both (NIC+CPU) reflects in CPU load. 
In linux use top/vmstat (be aware of user/system load when testing FTP). 
FTP-Performance depends heavily on the FTP-Server you use (vsftpd is a 
good one used by kernel.org).

Sascha.
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[gentoo-user] 1000Mbps NIC Getting 100Mbps speeds

[fire-eyes]

I have installed a 1000Mbps NIC in my system. This is the system some of
you read about me where I was trying to swap the names of eth0 and eth1
so maybe that has something to do with my problem.

The light on the NIC shows 1000Mbps link, as does the switch it is
connected to. Kernel messages show the link as autonegotiated, and
1000Mbps.

The only odd one out is mii-tool which claims eth0: negotiated
100baseTx-FD, link ok

I also tried using ethtool to set it at 1000Mbps anyway via ethtool -s
eth0 speed 1000 , and the kernel again spits out messages about a
1000Mbps link being up just fine. mii-tool still says the same as above,
however.

The problem is that I get speeds just as if it were a 100Mbps link,
starting at about 9MB/s then dropping to about 8.

As noted above I had two NIC's. One was an onboard 100Mbps, and the
second an add on 64-bit 1000Mbps. I had to do some tweaking with nameif
to get the 1000Mbps as eth0, and the 100Mbps as eth1. The reasons why I
wanted this really don't matter.

Making things more confusing, last night when I first applied the nameif
changes, I DID see 1000Mbps speed transfers.

I saw exactly this behavior in the past, what was happening was the
traffic was going right back out the 100Mbps and thus we had 100Mbps
speeds. However this time I've disabled the 100Mbps, even unplugged it.

There are no unusual routing entries. I am not using iptables.

I'm stumped here, any ideas?

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