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Date:      Tue, 26 Jan 2010 10:56:30 PST
From:      Dieter <freebsd@sopwith.solgatos.com>
To:        freebsd-firewire@freebsd.org, bug-followup@freebsd.org
Subject:   Re: kern/118093: firewire bus reset hogs CPU, causing data to be lost 
Message-ID:  <201001261856.SAA13144@sopwith.solgatos.com>

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> Looks like the kernel printf takes a *lot* of CPU, and
> somehow locks out Ethernet.

Looking through man pages working on an unrelated problem, I found:

man timed says:

     Messages printed by the kernel on the system console occur with inter-
     rupts disabled.  This means that the clock stops while they are printing.
     A machine with many disk or network hardware problems and consequent mes-
     sages cannot keep good time by itself.  Each message typically causes the
     clock to lose a dozen milliseconds.

If a kernel printf disables Ethernet interrupts for 12 milliseconds,
that would create the problem.



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