Date: Wed, 27 Jan 2010 05:20:02 GMT From: Dieter <freebsd@sopwith.solgatos.com> To: freebsd-firewire@FreeBSD.org Subject: Re: kern/118093: firewire bus reset hogs CPU, causing data to be lost Message-ID: <201001270520.o0R5K2ek089320@freefall.freebsd.org>
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The following reply was made to PR kern/118093; it has been noted by GNATS.
From: Dieter <freebsd@sopwith.solgatos.com>
To: freebsd-firewire@freebsd.org, bug-followup@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.
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