Re: Bug#618930: High network latency with ralink usb wireless device

Re: Bug#618930: High network latency with ralink usb wireless device

[Richard Kettlewell]

(see also bugs.debian.org/618930 though AFAIK everything important is 
reproduced in this message.)

On 19/03/2011 17:30, Ben Hutchings wrote:
> Sorry, no.  Please report this upstream to
> linux-wireless@vger.kernel.org and cc the bug address.

I have a TP-Link TL-WN321G USB wireless adapter, which is a badged 
Ralink RT2070.  Under Debian's 2.6.32 this worked smoothly with 
rt2870sta.  On upgrading to Debian's 2.6.38, however, only rt2800usb was 
available and with that I found that ping latency is around 600ms.

== Under 2.6.32, with rt2870sta ==

richard@violeer:~$ uname -a
Linux violeer 2.6.32-5-686 #1 SMP Wed Jan 12 04:01:41 UTC 2011 i686 
GNU/Linux
richard@violeer:~$ iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     Ralink STA  ESSID:"wlan.anjou.terraraq.org.uk" 
Nickname:"RT2870STA"
           Mode:Managed  Frequency=2.442 GHz  Access Point: 
00:0F:CB:A0:0C:70
           Bit Rate=54 Mb/s
           RTS thr:off   Fragment thr:off
           Link Quality=100/100  Signal level:-45 dBm  Noise level:-83 dBm
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:0  Invalid misc:0   Missed beacon:0

richard@sfere:~$ ping -qc10 violeer
PING violeer.wlan.anjou.terraraq.org.uk (172.31.59.138) 56(84) bytes of 
data.

--- violeer.wlan.anjou.terraraq.org.uk ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9013ms
rtt min/avg/max/mdev = 0.973/1.094/1.490/0.141 ms

== Under 2.6.38, with rt2800usb ==

richard@violeer:~$ uname -a
Linux violeer 2.6.38-1-686 #1 SMP Wed Mar 16 17:37:47 UTC 2011 i686 
GNU/Linux
richard@violeer:~$ iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     IEEE 802.11bg  ESSID:"wlan.anjou.terraraq.org.uk"
           Mode:Managed  Frequency:2.442 GHz  Access Point: 
00:0F:CB:A0:0C:70
           Bit Rate=18 Mb/s   Tx-Power=20 dBm
           Retry  long limit:7   RTS thr:off   Fragment thr:off
           Power Management:on
           Link Quality=67/70  Signal level=-43 dBm
           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
           Tx excessive retries:2  Invalid misc:6   Missed beacon:0


richard@sfere:~$ ping -qc10 violeer
PING violeer.wlan.anjou.terraraq.org.uk (172.31.59.138) 56(84) bytes of 
data.

--- violeer.wlan.anjou.terraraq.org.uk ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9006ms
rtt min/avg/max/mdev = 509.111/603.472/630.232/47.090 ms

== lsusb output ==

Bus 001 Device 002: ID 148f:2070 Ralink Technology, Corp. RT2070 
Wireless Adapter
Device Descriptor:
   bLength                18
   bDescriptorType         1
   bcdUSB               2.00
   bDeviceClass            0 (Defined at Interface level)
   bDeviceSubClass         0
   bDeviceProtocol         0
   bMaxPacketSize0        64
   idVendor           0x148f Ralink Technology, Corp.
   idProduct          0x2070 RT2070 Wireless Adapter
   bcdDevice            1.01
   iManufacturer           1 Ralink
   iProduct                2 802.11 g WLAN
   iSerial                 3 1.0
   bNumConfigurations      1
   Configuration Descriptor:
     bLength                 9
     bDescriptorType         2
     wTotalLength           67
     bNumInterfaces          1
     bConfigurationValue     1
     iConfiguration          0
     bmAttributes         0x80
       (Bus Powered)
     MaxPower              450mA
     Interface Descriptor:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        0
       bAlternateSetting       0
       bNumEndpoints           7
       bInterfaceClass       255 Vendor Specific Class
       bInterfaceSubClass    255 Vendor Specific Subclass
       bInterfaceProtocol    255 Vendor Specific Protocol
       iInterface              5 1.0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x01  EP 1 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x02  EP 2 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x03  EP 3 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x04  EP 4 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x05  EP 5 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0
       Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x06  EP 6 OUT
         bmAttributes            2
           Transfer Type            Bulk
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               0

== dmesg output ==

root@violeer:~# dmesg|grep -E rt2\|wlan
[   12.344624] Registered led device: rt2800usb-phy0::radio
[   12.344653] Registered led device: rt2800usb-phy0::assoc
[   12.344679] Registered led device: rt2800usb-phy0::quality
[   12.346539] usbcore: registered new interface driver rt2800usb
[   14.895564] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[   18.829895] wlan0: authenticate with 00:0f:cb:a0:0c:70 (try 1)
[   18.831281] wlan0: authenticated
[   20.432339] wlan0: associate with 00:0f:cb:a0:0c:70 (try 1)
[   20.434597] wlan0: RX AssocResp from 00:0f:cb:a0:0c:70 (capab=0x431 
status=0 aid=2)
[   20.434601] wlan0: associated
[   20.442967] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

Re: Bug#618930: High network latency with ralink usb wireless device

[Johannes Stezenbach]

On Sat, Mar 19, 2011 at 05:49:04PM +0000, Richard Kettlewell wrote:
> (see also bugs.debian.org/618930
...
> I have a TP-Link TL-WN321G USB wireless adapter, which is a badged
> Ralink RT2070.  Under Debian's 2.6.32 this worked smoothly with
> rt2870sta.  On upgrading to Debian's 2.6.38, however, only rt2800usb
> was available and with that I found that ping latency is around
> 600ms.
...
>           Power Management:on

I sent a patch to disable power save by default, but then work started
to fix it instead, but then stalled.  Seems like 2.6.38 shipped with
broken power save enabled by default.  Plese read the discussion
following my RFC patch:
http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2011-January/thread.html#3017

You can test if power saving causes your issue by disabling
it with "iwconfig wlan0 power off".

Johannes

Re: Bug#618930: High network latency with ralink usb wireless device

[Walter Goldens]

> 
> I sent a patch to disable power save by default, but then
> work started
> to fix it instead, but then stalled.  Seems like
> 2.6.38 shipped with
> broken power save enabled by default.  Plese read the
> discussion
> following my RFC patch:
> http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2011-January/thread.html#3017
> 
> You can test if power saving causes your issue by
> disabling
> it with "iwconfig wlan0 power off".
> 

Hi Johannes

Does this patch touches on lost and duplicate packets with rt3070 USB as well?

Walter


      

Re: Bug#618930: High network latency with ralink usb wireless device

[Richard Kettlewell]

On 19/03/2011 22:31, Johannes Stezenbach wrote:

> I sent a patch to disable power save by default, but then work started
> to fix it instead, but then stalled.  Seems like 2.6.38 shipped with
> broken power save enabled by default.  Plese read the discussion
> following my RFC patch:
> http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2011-January/thread.html#3017
>
> You can test if power saving causes your issue by disabling
> it with "iwconfig wlan0 power off".

That does the trick - thanks!

richard@sfere:~$ ssh violeer uname -a
Linux violeer 2.6.38-1-686 #1 SMP Wed Mar 16 17:37:47 UTC 2011 i686 
GNU/Linux
richard@sfere:~$ ping -qc10 violeer
PING violeer.wlan.anjou.terraraq.org.uk (172.31.59.138) 56(84) bytes of 
data.

--- violeer.wlan.anjou.terraraq.org.uk ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9016ms
rtt min/avg/max/mdev = 0.919/0.981/1.089/0.057 ms
richard@sfere:~$

ttfn/rjk

Re: High network latency with ralink usb wireless device

[Jonathan Nieder]

Hi Ben,

About a year ago, Richard Kettlewell wrote[1]:
> On 19/03/2011 22:31, Johannes Stezenbach wrote:

>> I sent a patch to disable power save by default, but then work started
>> to fix it instead, but then stalled.  Seems like 2.6.38 shipped with
>> broken power save enabled by default.  Plese read the discussion
>> following my RFC patch:
>> http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2011-January/thread.html#3017
>>
>> You can test if power saving causes your issue by disabling
>> it with "iwconfig wlan0 power off".
>
> That does the trick - thanks!

Therefore ever since version 2.6.38-2, Debian kernels have had
powersaving disabled on rt2800usb devices.

I think we should revisit this in light of

  v3.0-rc2~7^2~16^2~190 rt2x00: Add autowake support for USB hardware
  (2011-04-30)

though I wouldn't be surprised if testing ends up revealing some
followup patches introduced after v3.2 to be needed for it to work
well.  What do you think?

Thanks,
Jonathan

[1] http://bugs.debian.org/618930