Re: [Make-wifi-fast] per sta queuing - the ath9k statistics

[moeller0 <moeller0@gmx.de>]

Hi Dave,

Oh, this looks nice.

> On Mar 8, 2016, at 06:01 , Dave Taht <dave.taht@gmail.com> wrote:
> 
> I have put together some of the patches for fq_codel and per-station
> queuing inside the mac80211 portion of the stack flying around on
> linux-wireless, to no real visible effect as yet.

	Silly question: Is this really testing per-STA queuing? The client only connects to one AP, so all its upload packets can be aggregated into the same AMPDU; or rather in this case “per-station”/“per-AP” queueing degrades into a single queue, so what do you expect as visible effects here?

> 
> Mostly testing uploads at the moment, from an x86 based client. It's
> not clear if I have the code path enabled, either, nor how to check,
> from userspace. (?) Topology is
> 
> x86 <-wifi-> wndr3800 <-ethernet-> pi
> 
> Latency is still poor, throughput is down slightly. I will start
> printk-ing tomorrow.
> 
> I do have a few puzzling things
> 
> A) re the ath9k statistics
> 
> At the client (ubuntu x86, 4.5-rc7 + patches, Atheros AR5418 Wireless
> Network Adapter [AR5008E ) I see
> 
> http://pastebin.com/rvKJnc1y
> 
> AMPDUs Queued HW:            0          0         0         0
> AMPDUs Queued SW:            0          0         0         0
> AMPDUs Completed:      1098389       7050     14967         0
> 
> At the AP (cerowrt 3.10.50) I see
> 
> http://pastebin.com/RTt7MNT6
> 
> AMPDUs Queued SW:      3009455     364214    557331         0
> AMPDUs Completed:      2961055     363353    556982         0
> AMPDUs Retried:         115311       7833     21489         0
> 
> In both cases the TX-Pkts-all is close to the  AMPDUs completed figure.
> 
> B) In the regular packet captures I see no tcp losses. I can see in an
> aircap wifi retrying for every lost packet.

	I thought this is exactly what to expect from wifi’s attempts at “L1-retransmissions”, as long as the retransmissions ultimately are successful wifi will try to give the impression of a “perfect loss-less medium”, no?

> 
> C) I do not see any ECN marks (presumably would be generated by the
> codel implementation.)
> 
> D) I do see things nicely "fq"'d on the captures but that might be by
> cerowrt rather than the ieee mac
> 
> E) tc qdisc show dev wlp2s0 shows the tc layer qdisc disabled
> 
> qdisc noqueue 0: root refcnt 2
> 
> which does imply that at least part of the new codepath is working,
> but there are no stats out of that side yet...
> 
> Ah, well, at least the patchset compiled and didn't crash the box.
> 
> --
> Dave Täht
> Let's go make home routers and wifi faster! With better software!
> https://www.gofundme.com/savewifi
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