kern/118093: firewire bus reset hogs CPU, causing data to be lost

[Dieter]

The following reply was made to PR kern/118093; it has been noted by GNATS.

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

 > 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.