[RPI-B] [HEADS UP] DWC OTG TX path optimisation for 11-current

[Svatopluk Kraus]

On Wed, Jul 29, 2015 at 1:01 PM, Hans Petter Selasky <hps at selasky.org> wrote:
> On 07/29/15 12:42, Svatopluk Kraus wrote:
>>
>> On Wed, Jul 29, 2015 at 12:31 PM, Hans Petter Selasky <hps at selasky.org>
>> wrote:
>>>
>>> On 07/29/15 12:08, Svatopluk Kraus wrote:
>>>>
>>>>
>>>> On Tue, Jul 28, 2015 at 9:36 AM, Hans Petter Selasky <hps at selasky.org>
>>>> wrote:
>>>>>
>>>>>
>>>>> Hi,
>>>>>
>>>>> Can you test this:
>>>>>
>>>>> https://svnweb.freebsd.org/changeset/base/285935
>>>>>
>>>>
>>>> I'm hunting some strange behaviour slowdowning my set RPI2 - usb3 hub
>>>> - usb3 disk during buildworld, but I have noticed the following:
>>>>
>>>> make -j6 buildworld
>>>>
>>>> before r285935 -> 60145.29 real    350932.67 user     36402.54 sys
>>>> after r285935 -> 67831.38 real    196310.43 user     19135.73 sys
>>>>
>>>> The kernel before r285935 was day or two older.
>>>>
>>>> These are just one-run times, however the difference is quite big. The
>>>> change r285935 could influence the thing I'm investigating so it's
>>>> worse now, but still ...
>>>>
>>>
>>> Regarding build times you should also take "r285068" into account.
>>>
>>
>> Yes, I know about that. The r285068 was applied in both kernels.
>>
>
> Hi,
>
> The "sys" and "user" times are down. While the "real" time is up. That means
> more sleeping??? There is a knob in "hw.usb.umass.throttle" which you can
> set to slow down the disk access. Maybe it's reading files faster than
> before and then starts swapping?
>


The "sys" and "user" times are not reliable much. It was reported on
arm a few times. However, I wanted to report what I noticed just to
let anybody know about it. Maybe somebody would test r285068 for usb
disk too. I need to hunt down my problem firstly to be more sure about
this.

Just for your information, when I start buildworld, the system
responds very fast (console, ssh). After about one hour, it starts to
print the following warnings:

smsc0: warning: MII is busy
smsc0: warning: Failed to write register 0x114
smsc0: warning: Failed to read register 0x114
smsc0: warning: MII is busy
smsc0: warning: Failed to read register 0x118
smsc0: warning: Failed to write register 0x114
smsc0: warning: Failed to read register 0x114
smsc0: warning: MII is busy
smsc0: warning: Failed to write register 0x114
smsc0: warning: Failed to read register 0x114
smsc0: warning: MII is busy
smsc0: warning: Failed to read register 0x114
smsc0: warning: MII is busy
smsc0: warning: Failed to read register 0x114
smsc0: warning: MII is busy
smsc0: warning: Failed to write register 0x114
smsc0: warning: Failed to read register 0x114

and system responds very slow. When I stop buildworld (or when it
finishes), the warnings are still printed and system is still slow.
Even after several hours. When I disconnect everything (except the
disk itself), it does not help. When I set hw.usb.dwc_otg.debug=1,
there is quite a lot debug printing. Just now, I'm trying to know who
is responsible for such big trafic (almost nothing is running in
system). The generated load is so big that I'm not able to turn off
the debug sometimes.

Svata