* [ath9k-devel] Performance degradation when monitor interface is enabled
[not found] <50D27A8B.9000209@mailservices.uwaterloo.ca>
@ 2012-12-20 16:41 ` Ali Abedi
2012-12-30 14:03 ` Mohammed Shafi
0 siblings, 1 reply; 8+ messages in thread
From: Ali Abedi @ 2012-12-20 16:41 UTC (permalink / raw)
To: ath9k-devel
Hi,
I am writing this response to my own question since I have found a
workaround for this problem and this may help others as well.
So the problem is that if you have an interface wlan0 in managed mode
and then add another interface wlan1 in monitor mode it lowers your
outgoing throughput. It does not affect the incoming traffic though. The
trick is to add the monitor interface wlan1 then remove wlan0 by using
"iw dev wlan0 del" and then create wlan0 again. This way the incoming
and outgoing traffic is not affected by the monitor interface. This can
be caused by a bug in the driver. Those folks who know more about this
part of the driver may figure out what is going on after seeing this
solution.
Best,
Ali
On 23/10/2012 3:06 PM, Ali Abedi wrote:
> Hello,
>
> I asked this question once before but didn't get a satisfying answer. In
> our experiments, with two laptops running Ath9k driver we get about 29
> Mbps bandwidth (802.11g configuration + UDP traffic), but when the
> monitor mode interface is enabled on the sender the throughput drops to
> 25 Mbps. This is not a performance issue. The performance is unaffected
> if monitor mode interface is enabled on the receiver (no monitor
> interface on sender). I really appropriate your answer.
>
> Regards,
> Ali Abedi
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-12-20 16:41 ` [ath9k-devel] Performance degradation when monitor interface is enabled Ali Abedi
@ 2012-12-30 14:03 ` Mohammed Shafi
0 siblings, 0 replies; 8+ messages in thread
From: Mohammed Shafi @ 2012-12-30 14:03 UTC (permalink / raw)
To: ath9k-devel
On Thu, Dec 20, 2012 at 10:11 PM, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
> Hi,
> I am writing this response to my own question since I have found a
> workaround for this problem and this may help others as well.
> So the problem is that if you have an interface wlan0 in managed mode
> and then add another interface wlan1 in monitor mode it lowers your
> outgoing throughput. It does not affect the incoming traffic though. The
> trick is to add the monitor interface wlan1 then remove wlan0 by using
> "iw dev wlan0 del" and then create wlan0 again. This way the incoming
> and outgoing traffic is not affected by the monitor interface. This can
> be caused by a bug in the driver. Those folks who know more about this
> part of the driver may figure out what is going on after seeing this
> solution.
sure, lets take a look at this(new year). if its a straight forward one
we should go ahead and fix it.
>
> Best,
> Ali
>
> On 23/10/2012 3:06 PM, Ali Abedi wrote:
>> Hello,
>>
>> I asked this question once before but didn't get a satisfying answer. In
>> our experiments, with two laptops running Ath9k driver we get about 29
>> Mbps bandwidth (802.11g configuration + UDP traffic), but when the
>> monitor mode interface is enabled on the sender the throughput drops to
>> 25 Mbps. This is not a performance issue. The performance is unaffected
>> if monitor mode interface is enabled on the receiver (no monitor
>> interface on sender). I really appropriate your answer.
>>
>> Regards,
>> Ali Abedi
>> _______________________________________________
>> ath9k-devel mailing list
>> ath9k-devel at lists.ath9k.org
>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>
>
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
--
thanks,
shafi
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] ath9k_htc and reported mactime
@ 2012-10-21 2:32 Thomas Pedersen
2012-10-22 14:31 ` Adrian Chadd
0 siblings, 1 reply; 8+ messages in thread
From: Thomas Pedersen @ 2012-10-21 2:32 UTC (permalink / raw)
To: ath9k-devel
Hi list,
We're seeing some issue with reported mactime by the ath9k_htc (AR9271)
card. Here is a mesh node sampling peer beacons:
[ 327.928774] got beacon from 00:03:7f:10:4e:1a at 80969926, now is:
80940131. offset == 29795
[ 329.716530] got beacon from 64:70:02:0a:4e:a8 at 82824946, now is:
82727604. offset == 97342
[ 329.974276] got beacon from 00:03:7f:10:4d:f7 at 83082820, now is:
82985314. offset == 97506
[ 329.977528] got beacon from 00:03:7f:10:4e:1a at 83084622, now is:
82988562. offset == 96060
[ 331.764782] got beacon from 64:70:02:0a:4e:a8 at 84774638, now is:
84775531. offset == -893
[ 332.022278] got beacon from 00:03:7f:10:4e:1a at 85064980, now is:
85033000. offset == 31980
[ 332.025529] got beacon from 00:03:7f:10:4d:f7 at 85033451, now is:
85036249. offset == -2798
[ 333.814536] got beacon from 64:70:02:0a:4e:a8 at 86824159, now is:
86824975. offset == -816
[ 334.260908] got beacon from 00:03:7f:10:4e:11 at 87270487, now is:
87271277. offset == -790
[ 335.861412] got beacon from 64:70:02:0a:4e:a8 at 89100008, now is:
88871534. offset == 228474
[ 336.119176] got beacon from 00:03:7f:10:4d:f7 at 89128456, now is:
89129238. offset == -782
[ 336.308535] got beacon from 00:03:7f:10:4e:11 at 89317801, now is:
89318590. offset == -789
[ 337.909662] got beacon from 64:70:02:0a:4e:a8 at 90951396, now is:
90919468. offset == 31928
[ 338.168034] got beacon from 00:03:7f:10:4e:1a at 91209720, now is:
91177797. offset == 31923
[ 338.171285] got beacon from 00:03:7f:10:4d:f7 at 91211047, now is:
91181053. offset == 29994
[ 338.356286] got beacon from 00:03:7f:10:4e:11 at 91463481, now is:
91366022. offset == 97459
[ 338.734784] got beacon from f8:d1:11:65:92:e4 at 91743653, now is:
91744461. offset == -808
[ 339.958041] got beacon from 64:70:02:0a:4e:a8 at 92966623, now is:
92967531. offset == -908
[ 340.217914] got beacon from 00:03:7f:10:4d:f7 at 93226490, now is:
93227356. offset == -866
[ 340.408290] got beacon from 00:03:7f:10:4e:11 at 93449578, now is:
93417704. offset == 31874
[ 342.006291] got beacon from 64:70:02:0a:4e:a8 at 95014620, now is:
95015461. offset == -841
[ 342.264413] got beacon from 00:03:7f:10:4e:1a at 95272637, now is:
95273538. offset == -901
[ 342.453286] got beacon from 00:03:7f:10:4e:11 at 95461607, now is:
95462386. offset == -779
[ 342.833168] got beacon from f8:d1:11:65:92:e4 at 95939657, now is:
95842204. offset == 97453
The number after "at" is rx_status->mactime, "now" is drv_get_tsf(), and
offset (ie. stack delay) is mactime - tsf. RX_FLAG_MACTIME_MPDU is on for
all frames, and mesh sync is not adjusting the TSF.
How can we possibly receive frames from the future!?
Thanks in advance,
Thomas
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [ath9k-devel] ath9k_htc and reported mactime
2012-10-21 2:32 [ath9k-devel] ath9k_htc and reported mactime Thomas Pedersen
@ 2012-10-22 14:31 ` Adrian Chadd
2012-10-23 19:06 ` [ath9k-devel] Performance degradation when monitor interface is enabled Ali Abedi
0 siblings, 1 reply; 8+ messages in thread
From: Adrian Chadd @ 2012-10-22 14:31 UTC (permalink / raw)
To: Thomas Pedersen; +Cc: ath9k-devel, linux-wireless, Bob Copeland
Hi,
On 20 October 2012 19:32, Thomas Pedersen <thomas@cozybit.com> wrote:
> Hi list,
>
> We're seeing some issue with reported mactime by the ath9k_htc (AR9271)
> card. Here is a mesh node sampling peer beacons:
>
[snip]
> The number after "at" is rx_status->mactime, "now" is drv_get_tsf(), and
> offset (ie. stack delay) is mactime - tsf. RX_FLAG_MACTIME_MPDU is on for
> all frames, and mesh sync is not adjusting the TSF.
>
> How can we possibly receive frames from the future!?
>
1) Are you correctly merging the TSF32 values? Are you comparing TSF32
to TSF64, are you converting 32->64, etc? TSF32 wraps pretty quickly
and there's some kooky logic needed to make sure your TSF64 calculated
value is correct.
2) Are all your mesh nodes synchronised? Why don't you print out the
timestamp inside the beacon frame as well, and compare whether they're
all in reasonable sync?
Adrian
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-22 14:31 ` Adrian Chadd
@ 2012-10-23 19:06 ` Ali Abedi
2012-10-23 19:20 ` Adrian Chadd
0 siblings, 1 reply; 8+ messages in thread
From: Ali Abedi @ 2012-10-23 19:06 UTC (permalink / raw)
To: ath9k-devel
Hello,
I asked this question once before but didn't get a satisfying answer. In
our experiments, with two laptops running Ath9k driver we get about 29
Mbps bandwidth (802.11g configuration + UDP traffic), but when the
monitor mode interface is enabled on the sender the throughput drops to
25 Mbps. This is not a performance issue. The performance is unaffected
if monitor mode interface is enabled on the receiver (no monitor
interface on sender). I really appropriate your answer.
Regards,
Ali Abedi
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-23 19:06 ` [ath9k-devel] Performance degradation when monitor interface is enabled Ali Abedi
@ 2012-10-23 19:20 ` Adrian Chadd
2012-10-23 20:36 ` Ali Abedi
0 siblings, 1 reply; 8+ messages in thread
From: Adrian Chadd @ 2012-10-23 19:20 UTC (permalink / raw)
To: ath9k-devel
On 23 October 2012 12:06, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
> Hello,
>
> I asked this question once before but didn't get a satisfying answer. In
> our experiments, with two laptops running Ath9k driver we get about 29
> Mbps bandwidth (802.11g configuration + UDP traffic), but when the
> monitor mode interface is enabled on the sender the throughput drops to
> 25 Mbps. This is not a performance issue. The performance is unaffected
> if monitor mode interface is enabled on the receiver (no monitor
> interface on sender). I really appropriate your answer.
Start by looking at what's different. The only real change monitor
mode makes int he driver is fondling the RX filter.
It's possible that with monitor mode on, there's more stuff being
punted up to the driver on the receive side (all the other stuff in
the air) and that's causing things to slow down.
Adrian
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-23 19:20 ` Adrian Chadd
@ 2012-10-23 20:36 ` Ali Abedi
2012-10-23 20:51 ` Adrian Chadd
0 siblings, 1 reply; 8+ messages in thread
From: Ali Abedi @ 2012-10-23 20:36 UTC (permalink / raw)
To: ath9k-devel
Thanks Adrian. But there is no problem on the receiver side I assume
(monitor mode is not enabled on the receiver). There are gaps between
frames sent by the sender. It seems that the sender is waiting or doing
something between frames (other than back-off, DIFS, ...) when the
monitor mode is enabled on the sender.
Ali
On 10/23/2012 3:20 PM, Adrian Chadd wrote:
> On 23 October 2012 12:06, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
>> Hello,
>>
>> I asked this question once before but didn't get a satisfying answer. In
>> our experiments, with two laptops running Ath9k driver we get about 29
>> Mbps bandwidth (802.11g configuration + UDP traffic), but when the
>> monitor mode interface is enabled on the sender the throughput drops to
>> 25 Mbps. This is not a performance issue. The performance is unaffected
>> if monitor mode interface is enabled on the receiver (no monitor
>> interface on sender). I really appropriate your answer.
> Start by looking at what's different. The only real change monitor
> mode makes int he driver is fondling the RX filter.
>
> It's possible that with monitor mode on, there's more stuff being
> punted up to the driver on the receive side (all the other stuff in
> the air) and that's causing things to slow down.
>
>
> Adrian
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-23 20:36 ` Ali Abedi
@ 2012-10-23 20:51 ` Adrian Chadd
2012-10-25 19:46 ` Ali Abedi
0 siblings, 1 reply; 8+ messages in thread
From: Adrian Chadd @ 2012-10-23 20:51 UTC (permalink / raw)
To: ath9k-devel
On 23 October 2012 13:36, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
> Thanks Adrian. But there is no problem on the receiver side I assume
> (monitor mode is not enabled on the receiver). There are gaps between frames
> sent by the sender. It seems that the sender is waiting or doing something
> between frames (other than back-off, DIFS, ...) when the monitor mode is
> enabled on the sender.
I've no idea. You can try manually overriding the RX filter register
when monitor mode is enabled. See if that fixes it.
Adrian
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-23 20:51 ` Adrian Chadd
@ 2012-10-25 19:46 ` Ali Abedi
2012-10-25 19:52 ` abhinav narain
0 siblings, 1 reply; 8+ messages in thread
From: Ali Abedi @ 2012-10-25 19:46 UTC (permalink / raw)
To: ath9k-devel
Thanks for the answers. The performance issue theory doesn't make sense
as we get the same lower (and stable) throughput on different machines
with difference CPU powers or when power saving mode is enabled/disabled
(which changes CPU clock frequency) on this machines.
The interesting thing is that when I remove the monitor interface the
throughput remains the same (low). Isn't this a bug?
Thanks,
Ali
On 10/23/2012 4:51 PM, Adrian Chadd wrote:
> On 23 October 2012 13:36, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
>> Thanks Adrian. But there is no problem on the receiver side I assume
>> (monitor mode is not enabled on the receiver). There are gaps between frames
>> sent by the sender. It seems that the sender is waiting or doing something
>> between frames (other than back-off, DIFS, ...) when the monitor mode is
>> enabled on the sender.
> I've no idea. You can try manually overriding the RX filter register
> when monitor mode is enabled. See if that fixes it.
>
>
> Adrian
^ permalink raw reply [flat|nested] 8+ messages in thread
* [ath9k-devel] Performance degradation when monitor interface is enabled
2012-10-25 19:46 ` Ali Abedi
@ 2012-10-25 19:52 ` abhinav narain
0 siblings, 0 replies; 8+ messages in thread
From: abhinav narain @ 2012-10-25 19:52 UTC (permalink / raw)
To: ath9k-devel
Can you elaborate on what is the bug exactly?
By this mail, you have proved; monitor mode doesn't cause any throughput
degradation !
You should see if the channel is really bad causing the throughput to go
down.
-
Abhinav Narain
On Thu, Oct 25, 2012 at 3:46 PM, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
> Thanks for the answers. The performance issue theory doesn't make sense
> as we get the same lower (and stable) throughput on different machines
> with difference CPU powers or when power saving mode is enabled/disabled
> (which changes CPU clock frequency) on this machines.
> The interesting thing is that when I remove the monitor interface the
> throughput remains the same (low). Isn't this a bug?
>
> Thanks,
> Ali
>
>
> On 10/23/2012 4:51 PM, Adrian Chadd wrote:
> > On 23 October 2012 13:36, Ali Abedi <a2abedi@uwaterloo.ca> wrote:
> >> Thanks Adrian. But there is no problem on the receiver side I assume
> >> (monitor mode is not enabled on the receiver). There are gaps between
> frames
> >> sent by the sender. It seems that the sender is waiting or doing
> something
> >> between frames (other than back-off, DIFS, ...) when the monitor mode is
> >> enabled on the sender.
> > I've no idea. You can try manually overriding the RX filter register
> > when monitor mode is enabled. See if that fixes it.
> >
> >
> > Adrian
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>
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[not found] <50D27A8B.9000209@mailservices.uwaterloo.ca>
2012-12-20 16:41 ` [ath9k-devel] Performance degradation when monitor interface is enabled Ali Abedi
2012-12-30 14:03 ` Mohammed Shafi
2012-10-21 2:32 [ath9k-devel] ath9k_htc and reported mactime Thomas Pedersen
2012-10-22 14:31 ` Adrian Chadd
2012-10-23 19:06 ` [ath9k-devel] Performance degradation when monitor interface is enabled Ali Abedi
2012-10-23 19:20 ` Adrian Chadd
2012-10-23 20:36 ` Ali Abedi
2012-10-23 20:51 ` Adrian Chadd
2012-10-25 19:46 ` Ali Abedi
2012-10-25 19:52 ` abhinav narain
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