[ath9k-devel] ath9k ps poll performance

[Satanand Burla]

Hi,
I have AR9285 card on a netbook and I am using the latest compat-wirless drivers from http://wireless.kernel.org/download/compat-wireless-2.6/compat-wireless-2.6.tar.bz2

I am trying to use PS POLL on the ath9k driver, So I applied this
http://kernel.org/pub/linux/kernel/people/mcgrof/patches/ath9k/2009-12-08/ath9k-ps-enable.patch
patch from here on top of latest compat-wireless.

I have tried to use only pspoll without mac80211's dynamic_ps_timeout by setting the dynamic_ps_timeout to 0.

using
iwconfig wlan0 power timeout 0
iwconfig wlan0 power on.

I do not have any connection problems with this setup (as reported by others http://bugzilla.kernel.org/show_bug.cgi?id=14267) but I find that the performance is very slow.

for example with the same wep AP, I get around 150 to 200 Kbps without enabling ps poll. but if I enable ps poll with the above settings, I get only around 20 Kbps and the packet loss is around 20 to 30%.

My question is, is this the expected speed drop when turning on ps poll ? Or is this a problem with the driver that still needs to be addressed ?

I did enable ATH_DBG_PS and the ps poll sequence seems to going well ( detecting aid in tim, sending ps poll frame, picking buffered frames , going back to sleep).

I have also verified that the following patchset is already applied on the latest compat-wireless that I am trying. Unfortunately I am stuck with a 2.6.27 kernel and cannot test the latest wireless testing tree.

http://kernel.org/pub/linux/kernel/people/mcgrof/patches/ath9k/2009-12-08/for-2.6.32/


Any help will be highly appreciated.


Here is the lspci -vv of my ath9k card Please let me know if any other information is needed.


05:00.0 Network controller: Atheros Communications Inc. Device 002b (rev 01)
Subsystem: Askey Computer Corp. Device 7167
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR+ <PERR- INTx-
Latency: 0, Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 16
Region 0: Memory at f0100000 (64-bit, non-prefetchable) [size=64K]
Capabilities: [40] Power Management version 3
Flags: PMEClk- DSI- D1+ D2- AuxCurrent=375mA PME(D0+,D1+,D2-,D3hot+,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [50] Message Signalled Interrupts: Mask- 64bit- Count=1/1 Enable-
Address: 00000000 Data: 0000
Capabilities: [60] Express (v2) Legacy Endpoint, MSI 00
DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
MaxPayload 128 bytes, MaxReadReq 512 bytes
DevSta: CorrErr+ UncorrErr+ FatalErr- UnsuppReq+ AuxPwr- TransPend-
LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Latency L0 <512ns, L1 <64us
ClockPM- Suprise- LLActRep- BwNot-
LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- Retrain- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
DevCap2: Completion Timeout: Not Supported, TimeoutDis+
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-
LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-, Selectable De-emphasis: -6dB
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -6dB
Kernel driver in use: ath9k

Regards,
Satanand

[Kalle Valo]

for example with the same wep AP, I get around 150 to 200 Kbps
without enabling ps poll.

That's very low. What kind of test are you using here?

but if I enable ps poll with the above settings, I get only around
20 Kbps and the packet loss is around 20 to 30%.
My question is, is this the expected speed drop when turning on ps
poll ? Or is this a problem with the driver that still needs to be
addressed ?

With PS-Poll (ie. timeout is zero) you should still get in range of
megabits per second and no packet loss. So something is wrong.

[Satanand Burla]

Post by Kalle Valo

for example with the same wep AP, I get around 150 to 200 Kbps
without enabling ps poll.

That's very low. What kind of test are you using here?

Just an ftp from kernel.org.

Post by Kalle Valo

but if I enable ps poll with the above settings, I get only around
20 Kbps and the packet loss is around 20 to 30%.
My question is, is this the expected speed drop when turning on ps
poll ? Or is this a problem with the driver that still needs to be
addressed ?

With PS-Poll (ie. timeout is zero) you should still get in range of
megabits per second and no packet loss. So something is wrong.

Thank you.

Satanand.