Polling for ath driver

[Nate Nielsen]

Sam Leffler wrote:
> I see no statistics; are you sure you are not being pounded by phy
> errors. 

I've put together a small patch to the ath driver which exposes some
interupt statistic sysctls, and a small shell script to read these and
list them once per second. Both are attached.

Here are the results from the hostap box, configured like so:

ath0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 10.9.6.1 netmask 0xffffff00 broadcast 10.9.6.255
        ether 00:15:6d:10:17:03
        media: IEEE 802.11 Wireless Ethernet autoselect <hostap>
        status: associated
        ssid blah channel 165 bssid 00:15:6d:10:17:03
        authmode OPEN privacy OFF txpowmax 57 dtimperiod 1 bintval 100

When not active, we see (rx interrupts, tx interrupts, and all other
interrupts, respectively, one line per second):

RX:0  TX:0  OTH:10
RX:0  TX:0  OTH:11
RX:0  TX:0  OTH:10
RX:0  TX:0  OTH:11
RX:0  TX:0  OTH:10
RX:0  TX:0  OTH:11
RX:0  TX:0  OTH:10
RX:0  TX:0  OTH:11
RX:0  TX:0  OTH:10
RX:0  TX:0  OTH:10

I'm guessing the 10 or 11 interrupts per second are softawre beacon
interrupts. I did not spend time verifying this. Once we put load
through box (around 20+ Mb/s, two TCP streams, both directions
simultaneously):

RX:2377  TX:506  OTH:12
RX:2209  TX:509  OTH:10
RX:2118  TX:465  OTH:11
RX:2143  TX:482  OTH:10
RX:2145  TX:496  OTH:11
RX:2154  TX:493  OTH:10
RX:2123  TX:507  OTH:10
RX:2089  TX:471  OTH:11
RX:2021  TX:451  OTH:9
RX:2148  TX:496  OTH:10

As you noted the TX interrupts are mitigated.

During this time we have a normal amount of phy errors:

# athstats ath0 | cut -c 62-70
  phyerr
    2170
       0
      64
      71
      99
      77
     102
      87
      68
      72
      65

> You haven't even answered my question about what ath devices
> you're using.

Sorry bout that. These are 802.11a Mini-PCI radios, the chipset is
actually marked 'AR5213A' but I guess it's treated as a 5212:

<Atheros 5212> mem 0xe1000000-0xe100ffff irq 10 at device 10.0 on pci0
mac 5.9 phy 4.3 radio 3.6

Cheers,
Nate

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