All posts by Matthew Gillespie (admin)

C, Fiber, What?!

StarTech PEX10000SFP and locating modules in the Linux source.

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A friend contacted me recently with issues getting a new StarTech PCIe card with SFP+ slot working. He had hoped the card would work out of the box… but sometimes that doesn’t happen.

PEX10000SFP
Our test subject: The PEX10000SFP.

First off, let’s have a look at the PCI bus and see what the card has for a device ID number:

edge:~# lspci -k

…

01:06.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] ES1000 (rev 02)
Subsystem: Super Micro Computer Inc Device 1711
Kernel driver in use: radeon
03:00.0 Ethernet controller: Tehuti Networks Ltd. Device 4024
Subsystem: Tehuti Networks Ltd. Device 3015
edge:~#

As you can see, the VGA controller has a kernel module loaded and associated with it (radeon), however the Startech (Tehuti Networks) controller does not. With the device ID number in hand (0x4024), we can now look for it in the kernel source. If you don’t already have a copy of the Linux source, make sure to grab one via git:

edge:~# mkdir ~/git

edge:~# cd ~/git

edge: git# git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux

…

edge: git# cd ~/git/linux

edge:~# grep 0x4024 include/linux/pci_ids.h

edge:~#

Hmm…not a single hit. Let’s search for anything Tehuti related:

edge:~# grep DEVICE_ID_TEHUTI include/linux/pci_ids.h
#define PCI_DEVICE_ID_TEHUTI_3009 0x3009
#define PCI_DEVICE_ID_TEHUTI_3010 0x3010
#define PCI_DEVICE_ID_TEHUTI_3014 0x3014

So there’s device ID’s 0x3009, 0x3010, and 0x3014… but no 0x4024. So it doesn’t appear to be present in the source tree. But a quick search on the vendor website and the drivers are readily available for download – great news, but the running kernel (3.16.0-4-amd64) isn’t supported:

(From the Tehuti_TN4010.zip Readme file)

“- Supported kernels: 2.6.24 – 3.14.x”

edge:~# uname -r

3.16.0-4-amd64

And when trying to compile it, it fails:

…

/var/tmp/Linux/tn40.c: In function ‘bdx_ethtool_ops’:
/var/tmp/Linux/tn40.c:4021:5: error: implicit declaration of function ‘SET_ETHTOOL_OPS’ [-Werror=implicit-function-declaration]
SET_ETHTOOL_OPS(netdev, &bdx_ethtool_ops);
^
cc1: some warnings being treated as errors
/usr/src/linux-headers-3.16.0-4-common/scripts/Makefile.build:262: recipe for target ‘/var/tmp/Linux/tn40.o’ failed

So, let’s dig around and see if we can find the SET_ETHTOOL_OPS macro in the changelogs:

edge: git# cd ~/git/linux

edge:git# git log -S “#define SET_ETHTOOL_OPS”

…

commit 7ad24ea4bf620a32631d7b3069c3e30c078b0c3e
Author: Wilfried Klaebe <w-lkml@lebenslange-mailadresse.de>
Date: Sun May 11 00:12:32 2014 +0000

net: get rid of SET_ETHTOOL_OPS

net: get rid of SET_ETHTOOL_OPS

Dave Miller mentioned he’d like to see SET_ETHTOOL_OPS gone.
This does that.

Mostly done via coccinelle script:
@@
struct ethtool_ops *ops;
struct net_device *dev;
@@
– SET_ETHTOOL_OPS(dev, ops);
+ dev->ethtool_ops = ops;

Compile tested only, but I’d seriously wonder if this broke anything.

Suggested-by: Dave Miller <davem@davemloft.net>
Signed-off-by: Wilfried Klaebe <w-lkml@lebenslange-mailadresse.de>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Well, there’s the reason it won’t compile – the macro was recently removed. So how do we get the module to compile? Simple – just update the source to perform the same action that the macro used to do. Or to make things easy (although it’s overkill for a patch file), just apply a truly braindead patch:

edge: tmp# wget http://www.braindeadprojects.com/src/tn40.c.ethtool_ops.patch

edge: tmp# patch -p0 < tn40.c.ethtool_ops.patch

patching file Linux/tn40.c

And with a quick recompile, install and modprobe, we now have a working Startech card in our system:

edge: tmp# modprobe tn40xx

…

edge: tmp# lspci -k

…

03:00.0 Ethernet controller: Tehuti Networks Ltd. Device 4024
Subsystem: Tehuti Networks Ltd. Device 3015
Kernel driver in use: tn40xx

…

edge: tmp## ethtool eth2
Settings for eth2:
Supported ports: [ FIBRE ]
Supported link modes: 10000baseT/Full
Supported pause frame use: Symmetric
Supports auto-negotiation: No
Advertised link modes: 10000baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: No
Speed: Unknown!
Duplex: Full
Port: FIBRE
PHYAD: 0
Transceiver: external
Auto-negotiation: off
Link detected: no

I’ve passed along the information to Startech. It’s a pretty simple fix, so I’d expect to see it in their distributed source code soon. But in the meantime, if you’re working with this card and unable to get the kernel module to build, see if this solution will work for you.

Ubiquiti, What?!, Wireless

The Sunset on Lambs Gap

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A couple of months ago, I started to notice a few issues when watching YouTube videos at my home.  It seemed that the videos were taking longer to buffer, and a quick check of my Ubiquiti NanoBridge M5 (NMB5-25) revealed my signal had deteriorated from it’s usual -64dBm signal to around -75dBm. The Airmax Quality had also significantly tanked, now reading around 40%. An Airview scan didn’t seem to indicate any new interference:

Airview Before
The Access Point is in use.

Throughput tests to two on-network Speedtest.net Mini sites still showed decent rates, but it became obvious that TCP retransmissions were starting to significantly impact surfing the web. Unfortunately, I didn’t think to grab a tcpdump to support that theory.

Before Speedtest
Decent Throughput it would seem

I had been holding off installing the new NanoBeam M5 (NBE-M5-400) since I wanted to ensure they were stable. While I’ve not been burned by the problems with ToughCable or chain burnout problems on the Rocket Titanium M5’s, I’ve heard my fair share of grumbling from people that have. On the Ubiquiti forum people have mostly raved about the new units so I figured I’d see how well it performs.

On the roof of my home, I have a non-penetrating mount atop two anti-fatigue mats purchased from the Home Depot. The mats aren’t UV rated, something I didn’t consider until later. After a yearlong installation, the mats are in surprisingly good shape. I don’t anticipate having to replace them in the next two years based on their current wear.

The Mount.
Carrying 3 of these up a ladder makes you sleepy… that’s why there’s no fourth.

The NanoBridge M5 dish itself was still tightly connected to it’s mast, and the 3 concrete ballasts holding the mount in place seem to prevent any possible shifting.  Initially when my signal deteriorated, I thought a bird may have slammed into the dish or mount and somehow moved it, but I don’t believe this is the case. The more likely culprit is a tree.

Tree Clipping
A view from behind the new NanoBeam — I’m fairly certain I’m clipping the tree on the right.
Hey What's That Picture
Courtesy of heywhatsthat.com – the line to the tower.

I knew when I installed the link that it was very likely clipping the tree on the right. Our tower is slightly to the right of the valley.  Not particularly liking heights and trying to limit visibility from the street, I opted not to move the mount closer to the front of my home.  I may revisit that decision in the future. Before I removed the NanoBridge I did try to correct it’s position but was only able to receive around an average of -70dBm at best.

The NanoBridge M5
This is about where my signal settled.

Losing sunlight, I upgraded the dish to the NanoBeam M5. The only thing about the dish I dislike is that it has one U-bolt instead of two. I’m sure it’s ample but the NanoBridge’s 2 U-bolt configuration really seemed to hold it to the pole so that it couldn’t possibly be knocked out of alignment. My roof is mostly flat with a slight angle, so I wasn’t able to fully straighten the dish.

The Level
Do Not Point the Laser into Someone’s Eyes.

Installing the NanoBeam was quick and easy. The first thing that was obvious was the noise floor had gone from -93dBm to -103dBm. The signal was significantly improved, now running in the -63dBm range, and overall stats were a remarkable improvement over the NanoBridge.

NanoBeam Stats
A bit of a difference

 

Post Upgrade Speedtests
Zrrrrrrrrrroooooomm!

The week before I performed the upgrade, I finally added the Ubiquiti radio to my home Cacti installation. Forgive the ugly colors of the graphs (I plan of making them more visually appealing one day), but as Adam Savage says “The only difference between screwing around and science is writing it down“.  These graphs display a pretty clean-cut before and after of the upgrade, which took place at about 20:00.

Frequency in Use
I didn’t change frequencies, but here’s a graph.
Mo Memory
The NanoBeam has more memory than the NanoBridge.
CCQ
Client Connection Quality (not much of a change here)
Signal Graph
The signal is substantially improved.
Data Rates
My data rates improved.

I incorrectly saved the Airmax graph after the upgrade and only noticed the next day (that’s why this graph is hours after the others).

Airmax
Much better Airmax Quality.

I’m extremely pleased with the upgrade. My initial problems with YouTube buffering have gone away and three days later things are still going strong. In the end I had a chance to see a pretty cool sunset on Lambs Gap.

SunsetOnLambsGap
The Sunset on Lambs Gap
PHP, Ubiquiti, Wireless

Wireless Iperf Graphing – Part Two

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After dusting off the old source for my previous post, I started realizing one of the main limitations to Ubiquiperf — the results aren’t displayed real-time.  If they were, one could easily move radios around and see the impact almost instantly. This got me thinking, and not having worked in Java for a while I knew what to do: Fork JPerf and get to work:

Announcing: UbiquiJPerf
Announcing: UbiquiJPerf

It’s got a long way to go, and comments/suggestions are always welcome. Source (including a pre-compiled .jar) are available at github.

PHP, Ubiquiti, What?!, Wireless

Wireless Iperf Graphing

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About a year ago, we were doing some wireless throughput/interference testing at the office  to acclamate ourselves to the wireless world. Most importantly, we were trying to answer the question “Why can’t I just lease a 10 foot section on a tower and  install a zillion radios there?”

Despite having a handful of BCP design documents at hand, as well as input from established and respected members of the wireless community, the question kept seeming to pop up. So how does one present a worthwhile answer?

My solution was to build a small section of a tower leg on our back lot using a non-penetrating roof mount, 2 Ubiquiti Rocket M5 90 5G-20-90 degree sectors (mounted 90 degrees from each other, without shielding), 2 Nanostion M5 CPE’s, 4 laptops, and a couple of inverters and car batteries to power 2 of the laptops (the other 2 were run off extension cables).  The two laptops connected at the Access Point side ran as Iperf servers, each laptop ran as a client.

UbiquiperfLayout
Plug this in here, that in over there, and this cable.. here.

The thought was to grab Iperf and AirOS datapoints at every couple of seconds  and see “what happens when I do this?” “THIS ” generally entailed doing something BCPs warned against doing.

To gather the Iperf data and AirOS statistics, I put together a quick script i called “Ubiquiperf“. Basically it polls an iperf test every second, pulls the stats off the radio (Capacity, Quality, RSSI, etc) , generates a CSV file of all the data, and finally creates a graph using the jpgraph PHP libraries.

Due to weather conditions our testing was cut short and our initial results had a simple problem: we needed to turn the transmit power down on all the radios.

For a baseline, we performed a quick throughput test one at a time, where each Access Point operating on the same frequency could perform at about 85Mbps:

ap1-test1
AP1 Baseline
ap2-test1
AP2 Baseline

So what happens if I perform the same throughput test on both units but at the exact same time, over a longer duration?

ap1-test2
AP1 concurrent iperf test
ap2-test2
AP2 concurrent iperf

Well, it obviously cut off about 20Mbps from the first access point. Of course, the power on the radios really needs to be turned down so this test is unfortunately not worth much. We’ll be doing additional testing in the near future, and hope to have meaningful results that include mounts with and without RF Armor, Titanium model equipment, etc. I’ll publish our results when I can.

In the meantime, feel free to play with it yourself. Full PHP source is available on GitHub.