Can iperf work with no qos? (TCP mode)

[Rafał Miłecki]

W dniu 11 czerwca 2011 19:57 użytkownik Michael Büsch <m at bues.ch> napisał:
> On Sat, 11 Jun 2011 19:47:31 +0200
> Rafał Miłecki <zajec5 at gmail.com> wrote:
>
>> I can not get any results when trying to use iperf in TCP mode with
>> driver not supporting qos.
>>
>> Is this expected? Does iperf fill connection with so many packets,
>> it's not possible to get response from the iperf receiver? Should not
>> Linux somehow schedule packet to allow bi-direction communication,
>> even on really filled connection?
>
> iperf will only fill the best effort queue. At least that's what it did
> last time when I looked into the code.
> You can verify that with b43's ring statistics.

It's BE queue we create for qos=0 in b43:
else
	q = dev->pio.tx_queue_AC_BE;
so this should not limit iperf

As another test, I've just tried dma mode with qos=0. iperf was fine.

So now we know iperf does not need multiple queues. It seems that:
GOOD: b43 & dma & no qos
BAD: b43 & pio & no qos

In the second case connection is started (I can see that from "iperf
-s" on my receiving machine), but it seems sender does not receive any
confirmations.

-- 
Rafał