em driver regression

[Jack Vogel]

Only one device support by em does multiqueue right now, and that is
Hartwell, 82574.

Jack


On Thu, Apr 8, 2010 at 2:05 PM, Mike Tancsa <mike at sentex.net> wrote:

> At 04:56 PM 4/8/2010, Pyun YongHyeon wrote:
>
>> On Thu, Apr 08, 2010 at 02:31:18PM -0400, Mike Tancsa wrote:
>> > At 02:17 PM 4/8/2010, Pyun YongHyeon wrote:
>> >
>> > >Try this patch. It should fix the issue. It seems Jack forgot to
>> > >strip CRC bytes as old em(4) didn't strip it, probably to
>> > >workaround silicon bug of old em(4) controllers.
>> >
>> > Thanks! The attached patch does indeed fix the dhclient issue.
>> >
>> >
>> > >It seems there are also TX issues here. The system load is too high
>> > >and sometimes system is not responsive while TX is in progress.
>> > >Because I initiated TCP bulk transfers, TSO should reduce CPU load
>> > >a lot but it didn't so I guess it could also be related watchdog
>> > >timeouts you've seen. I'll see what can be done.
>> >
>> > Thanks for looking into that as well!!
>> >
>> >         ---Mike
>> >
>>
>> Mike,
>>
>> Here is patch I'm working on. This patch fixes high system load and
>> system is very responsive as before. But it seems there is still
>> some TX issue here. Bulk UDP performance is very poor(< 700Mbps)
>> and I have no idea what caused this at this moment.
>>
>> BTW, I have trouble to reproduce watchdog timeouts. I'm not sure
>> whether latest fix from Jack cured it. By chance does your
>> controller support multi TX/RX queues? You can check whether em(4)
>> uses multi-queues with "vmstat -i". If em(4) use multi-queue you
>> may have multiple irq output for em0.
>>
>
> Hi,
>        I will give it a try later tonight!  This one does not seem to.
>
> 0(ich10)# vmstat -i
> interrupt                          total       rate
> irq16: uhci0+                         30          0
> irq18: ehci0 uhci5                158419         17
> irq19: fwohci0++                      86          0
> irq21: uhci1                          17          0
> irq23: uhci3 ehci1                     2          0
> cpu0: timer                     18570305       1994
> irq256: igb0                          80          0
> irq257: igb0                         255          0
> irq258: igb0                          66          0
> irq259: igb0                          32          0
> irq260: igb0                           2          0
> irq261: igb1                        2679          0
> irq262: igb1                         998          0
> irq263: igb1                        2468          0
> irq264: igb1                        6361          0
> irq265: igb1                           2          0
> irq266: em0                        33910          3
> irq267: ahci1                      15317          1
> cpu1: timer                     18557074       1993
> cpu3: timer                     18557168       1993
> cpu2: timer                     18557108       1993
> Total                           74462379       7998
> 0(ich10)#
>
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> --------------------------------------------------------------------
> Mike Tancsa,                                      tel +1 519 651 3400
> Sentex Communications,                            mike at sentex.net
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> Cambridge, Ontario Canada                         www.sentex.net/mike
>
>