em driver regression

Mike Tancsa mike at sentex.net
Thu Apr 8 21:05:15 UTC 2010


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)#






--------------------------------------------------------------------
Mike Tancsa,                                      tel +1 519 651 3400
Sentex Communications,                            mike at sentex.net
Providing Internet since 1994                    www.sentex.net
Cambridge, Ontario Canada                         www.sentex.net/mike



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