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Date:      Sat, 28 Jun 2008 13:30:39 -0700
From:      Rudy <crapsh@monkeybrains.net>
To:        Jack Vogel <jfvogel@gmail.com>
Cc:        freebsd-net@freebsd.org
Subject:   Re: Seeking help understanding my "emX: watchdog timeout" messages
Message-ID:  <48669F6F.1050005@monkeybrains.net>
In-Reply-To: <485ECF20.6000607@monkeybrains.net>
References:  <20080516185813.H866@logos.sky.od.ua>	<2a41acea0805160904g7dcf9f58rf69ca5d0612945cc@mail.gmail.com>	<4853055C.2030303@MonkeyBrains.NET>	<48535A11.4020003@monkeybrains.net>	<48582C29.8030307@monkeybrains.net>	<2a41acea0806191055w5e112b8bsa57a8db2b177adbe@mail.gmail.com>	<485C0F07.7000408@monkeybrains.net>	<2a41acea0806201355y3b123462wc37280f28a9f4216@mail.gmail.com>	<485C41C5.4090706@monkeybrains.net>	<2a41acea0806201713m7a083b9dr10894c8a0845df8e@mail.gmail.com>	<485D5B9E.8020908@monkeybrains.net> <485ECF20.6000607@monkeybrains.net>

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Continuing the emX thread...
----------------------------------------

#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.

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

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.

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

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@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@mailbox.intel.com.

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

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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