Intel Cenrtrino Wireless-N 2230 low performance in Mageia

[bertaerts]

I have a Dell Inspiron 17R SE 7720 with Intel Centrino Wireless-N 2230.
It is connected to a BBOX3 VDSL modem/router at a speed of maximum 130 Mbps.
This speed is varying all the time with Mageia 4 x86_64 as OS, mostly 65 Mbps.

When I transfer files from my desktop PC running Windows 7 connected via ethernet port at 1 Gbps to the modem, I get speeds of 2.5 MB/s (20 Mbps) in the direction from notebook to desktop and 4.5 MB/s (36 Mbps) in direction from desktop to notebook. So wireless network is only passed once, as desktop is wired to modem.

When I use Windows 7 on my notebook I get a speed of 144 Mbps and transfer speeds of 9.5 MB/s (76 Mbps) in both directions.

How can I tune Mageia Linux to get the same transfer speeds as in Windows 7 ?

[bertaerts]

In Mageia Control Center / Hardware / Browse and configure hardware / Ethernetcard / Centrino Wireless-N 2230 / Set current driver options set following options:
swcrypto = 1 [using crypto in software (default 0 [hardware]) (int)]
11n_disable = 8 [ disable 11n functionality, bitmap: 1: full, 2: disable agg TX, 4: disable agg RX, 8 enable agg TX (uint) ]
This 8 seems a bit misuse of the disable 802.11n parameter... 11n is not disabled at all, it is to turn on a feature that is currently disabled in the kernel...
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=81571
Currently in the kernel Tx AMPDU is disabled, with the 8 it is enabled again.
A-MPDU: The concept of A-MPDU aggregation is to join Multiple MPDU sub frames with a single leading PHY header. A key difference from A-MSDU aggregation is that A-MPDU functions after the MAC header encapsulation process. This method offer higher MAC throughput compare to A-MSDU.
Reference: http://mrncciew.com/2013/04/11/a-mpdu-a-msdu/

I am not sure if I really need swcrypto parameter.

But currently I get transfer speeds of 6.5 MB/s (52 Mbps) in both directions.
Although that is a lot better than before, it is still far away from Windows 7 with 9.5 MB/s.

[jiml8]

How are you transferring files? Using what protocol? What desktop are you using on Mageia? KDE?

In what I think is the most likely case where you are using KDE and doing a drag and drop from one machine to the other (which would have you using SMB - samba, on the Mageia side), I think you will find that KDE performance doing that is simply abyssmal. I don't think this is a Mageia issue or a kernel driver issue, but a KDE issue.

I myself explored a substantially similar issue, starting with checking out why I could not stream videos from my NAS to my KDE-based Mageia workstation over SMB, and finally determining that data transfers done this way happened at a VERY low speed (see viewtopic.php?f=23&t=8143&p=50298&hilit=streaming+video&sid=0c7b5e7e41a7f4624cb8ee6874ab0373#p50298) for the details.

I suggest you find another way to transfer the data. Given that this is likely to be a common thing for you to do, you might want to try setting up NFS shares, or else configure to mount SMB shares rather than just drag and drop.

If you do figure out how to make drag and drop using KDE and SMB work well, please post your solution.

[martinw]

I see the same performance as bertaerts when transferring to/from a Mageia desktop using scp (copy via ssh). Connecting via a wired link instead of wireless gives a transfer speed of 144MB/sec, so it's clearly the wireless link that's the bottleneck for me.

Thanks for the tip about 11n_disable=8, bertaerts.

[doktor5000]

Additionally you may want to try 5ghz_disable=1

[bertaerts]

I indeed am using KDE.
And the type of file transfer was via Dolphin / Network / Add Network Folder / Microsoft Windows network drive.

I now did the following to mount the Windows network drives:
Mageia Control Center / Network Sharing / Configure Windows (R) shares
Choose machine and shared directory
Choose mount point and Mount
Adapt /etc/fstab to get write access for user bert: add uid=bert and gid=bert (otherwise read-only access)

Code: Select all

//hpe120be/DATA\040ALL /mnt/DATA-ALL cifs uid=bert,credentials=/etc/samba/auth.hpe120be.bert,gid=bert 0 0

This way the speeds becomes as good as in Windows 7:
notebook to desktop 10.3 MB/s but bottom right window shows incorrect 1018.4 MB/s and is not updated, but closed correctly after transfer finished
desktop to notebook 10.1 MB/s bottom right KDE info window shows average 9.0 MB/s

So the only problem that remains is that file transfer from notebook to desktop is not correctly handled by KDE info message in bottom right corner.
Also when watching the file size in Dolphin, it goes at very high speed to complete, while Network monitor is still very busy at 10 MB/s for a minute.

[doktor5000]

FWIW, the 11n_disable mask seems to benefit nearly every connection involving any Intel wireless chipset.
This is how I unload the relevant modules and set the option:

Code: Select all

modprobe -rf iwldvm; modprobe -rf iwlwifi; modprobe iwlwifi 11n_disable=8; service NetworkManager restart

Before this, got transfer rates of 1 to 1.5 MB/s even for larger sequential transfers (4 GB files) and after that,
sustained transfer rates over 70MB/s from cache and around 5MB/s for sustained transfers not in cache.

[bertaerts]

sustained transfer rates over 70MB/s from cache

That would be 560 Mbps, is it not 7 MB/s in stead of 70 MB/s ?

[doktor5000]

Nope, that were the numbers I saw. That's why I mentioned from cache ...
Although that's with an 802.11ac 867 Mbps adapter (which could theoretically achieve ~50 - 100MB/s against an 802.11ac device) - although in my case the other side was only 802.11n IIRC.

Even then I would have been happy to get into the range of 10 - 15 MB/s sustained transfers (802.11n should be able to achieve net ~18 MB/s) but was too lazy to dig further into it.
Also the 802.11n device discarded *a lot* of packages, but the transfer speed was 3 times as fast with 11n_disable=8 so I did not care further.