Seeking help understanding my "emX: watchdog timeout" messages

Rudy crapsh at monkeybrains.net
Sat Jun 28 20:30:44 UTC 2008


Continuing the emX thread...
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#man 4 em
      hw.em.txd
              Number of transmit descriptors allocated by the driver.  The
              default value is 256.  The 82542 and 82543-based adapters can
              handle up to 256 descriptors, while others can have up to 4096.

I just upped values in my loader.conf:
  hw.em.rxd=1024
  hw.em.txd=1024

Thanks Dmitriy -- your reply on jboss gave me idea to try tuning that value.

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I tried upping the rx_processing_limit on my active interfaces and that caused MORE watchdog 
timeout events.  In fact, they started to happen on em0 and em1 (previously not throwing errors).
  dev.em.0.rx_processing_limit=200
  dev.em.1.rx_processing_limit=200
  dev.em.2.rx_processing_limit=200
  dev.em.4.rx_processing_limit=200
I am going to keep those values in with the new hw.em.rxd settings and back them out if watchdog 
events persist.

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Questions to EM users:
  Do you use POLLING or MSI Interrupts with FreeBSD 7.x and PCIe Ethernet adapters?
  Do you see watchdog timeout events on your Intel adapters?

----------------------------------------

I emailed Intel and asked for help.  They referred me to this document (not very helpful):
  http://downloadmirror.intel.com/10957/ENG/README.txt

I replied and asked if other users are reporting watchdog timeout events.  The tech was less than 
helpful -- here was the response from adaptersuppor at mailbox.cps.intel.com:

 >> Please be aware that you are the first person who reports those “watchdog timeouts”.
 >>
 >> Please note that this is an intermittent behavior, we have not been able to
 >> determine exactly when that issue happens, and to which exact adapter under
 >> which exact circumstances, in the moment that we have a problem we are able
 >> to recreate many times this will become a “known issue” and most certainly
 >> it will be posted in our website under the adapters that has that issue.

Dude!  Take an ESL class.  I also CC'd freebsdnic at mailbox.intel.com.

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Last week I tried changing this setting:

>  dev.em.2.tx_int_delay: 33
>  dev.em.2.tx_abs_int_delay: 33

They did not help.



Rudy




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