I recently got an Asus USB-N13 USB Wireless-N adapter which apparently
uses a Ralink RT3072 chip. I'm using it with an Asus RT-N16 access point
running TomatoUSB. When running Windows the performance is reasonable
(about 80 Mbps in both directions). However under Fedora 16 (currently
kernel 3.1.2) the performance is abysmal (10 Mbps or less with lots of
packet loss). I'll post some debug information below.
I have another adapter, a Trendnet which apparently is an RT3070 and
uses the same driver, which works much better (about 50 Mbps) despite
being only a 150 Mbps chip (1X MIMO) as opposed to 300 Mbps (2X MIMO)
like the Asus. Looking at the Minstrel rc_stat output it seems like a
lot of the MCS8-15 rates are being tried but the success is quite poor -
I'm not sure if this is a cause of the poor performance or an effect..
While debugging this I also noticed that doing an rmmod on rt2800usb
with the adapter plugged in locks up the machine and then spews out soft
lockup stack traces on the console. I was only able to capture it off
the screen with a camera, but it basically is:
rt2x00usb_work_rxdone
process_one_work
worker_thread
kthread
kernel_thread_helper
The output repeats periodically and it always seems to involve either
rt2x00usb_work_rxdone or rt2x00usb_work_txdone so it seems like we're
spinning through those functions for some reason. I can post/send the
image if anyone wants more details from the stack trace.
Linux nicole 3.1.2-1.fc16.i686 #1 SMP Tue Nov 22 08:56:28 UTC 2011 i686
i686 i386 GNU/Linux
lsusb -vv:
Bus 001 Device 002: ID 0b05:1784 ASUSTek Computer, Inc. USB-N13 802.11n
Network Adapter [Ralink RT3072]
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0b05 ASUSTek Computer, Inc.
idProduct 0x1784 USB-N13 802.11n Network Adapter [Ralink RT3072]
bcdDevice 1.01
iManufacturer 1 Ralink
iProduct 2 802.11 n 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
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)
From ifconfig (after running some transfer speed tests):
RX packets:61207 errors:0 dropped:0 overruns:0 frame:0
TX packets:43886 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:78762017 (75.1 MiB) TX bytes:27862511 (26.5 MiB)
From iwconfig (some AP details removed):
wlan2 IEEE 802.11bgn
Mode:Managed Frequency:2.422 GHz
Bit Rate=65 Mb/s Tx-Power=27 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:on
Link Quality=70/70 Signal level=-37 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:836 Invalid misc:37 Missed beacon:0
rc_stats output from sysfs:
type rate throughput ewma prob this prob this succ/attempt
success attempts
HT20/LGI MCS0 6.0 96.0 100.0 0( 0)
17 27
HT20/LGI MCS1 11.2 95.4 100.0 0( 0)
11 13
HT20/LGI MCS2 16.0 96.8 100.0 0( 0)
12 15
HT20/LGI MCS3 10.3 49.5 0.0 0( 0)
57 143
HT20/LGI MCS4 4.3 15.4 0.0 0( 0)
38 167
HT20/LGI MCS5 3.7 11.1 0.0 0( 0)
96 248
HT20/LGI MCS6 11.1 30.6 0.0 0( 0)
255 452
HT20/LGI MCS7 20.4 52.2 0.0 0( 0)
11871 12290
HT20/LGI MCS8 5.0 42.5 0.0 0( 0)
18 38
HT20/LGI MCS9 9.2 44.1 0.0 0( 0)
17 42
HT20/LGI MCS10 12.7 45.3 100.0 0( 0)
24 69
HT20/LGI MCS11 10.8 32.0 0.0 0( 0)
66 293
HT20/LGI MCS12 7.7 18.0 0.0 0( 0)
74 361
HT20/LGI MCS13 11.7 23.9 0.0 0( 0)
69 348
HT20/LGI MCS14 16.3 31.3 0.0 0( 0)
99 369
HT20/LGI MCS15 20.3 37.3 0.0 0( 0)
392 632
HT20/SGI MCS0 6.9 100.0 100.0 0( 0)
1 1
HT20/SGI MCS1 12.9 100.0 100.0 0( 0)
1 1
HT20/SGI t MCS2 17.1 95.1 100.0 0( 0)
11 15
HT20/SGI MCS3 4.2 18.9 0.0 0( 0)
73 278
HT20/SGI MCS4 0.0 0.7 0.0 0( 0)
40 316
HT20/SGI MCS5 12.6 35.0 0.0 0( 0)
106 422
HT20/SGI MCS6 8.8 23.0 0.0 0( 0)
644 1063
HT20/SGI T PMCS7 40.3 97.7 100.0 2( 2)
28626 29571
HT20/SGI MCS8 7.4 57.4 100.0 0( 0)
25 47
HT20/SGI MCS9 5.4 24.1 0.0 0( 0)
18 65
HT20/SGI MCS10 0.0 2.8 0.0 0( 0)
31 161
HT20/SGI MCS11 9.6 26.8 100.0 0( 0)
54 386
HT20/SGI MCS12 12.7 27.9 0.0 0( 0)
65 448
HT20/SGI MCS13 10.9 21.3 0.0 0( 0)
94 464
HT20/SGI MCS14 15.7 29.0 0.0 0( 0)
219 560
HT20/SGI MCS15 19.8 35.0 0.0 0( 0)
365 597
Total packet count:: ideal 43018 lookaround 1308
Average A-MPDU length: 1.0
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