kern/118093: firewire bus reset hogs CPU, causing data to be
M. Warner Losh
imp at bsdimp.com
Tue Dec 16 23:10:04 PST 2008
The following reply was made to PR kern/118093; it has been noted by GNATS.
From: "M. Warner Losh" <imp at bsdimp.com>
To: freebsd at sopwith.solgatos.com
Cc: freebsd-firewire at freebsd.org, freebsd-drivers at freebsd.org,
bug-followup at freebsd.org
Subject: Re: kern/118093: firewire bus reset hogs CPU, causing data to be
Date: Tue, 16 Dec 2008 23:59:41 -0700 (MST)
In message: <200812170329.DAA17848 at sopwith.solgatos.com>
Dieter <freebsd at sopwith.solgatos.com> writes:
: Sean> Which file in dev/firewire are you looking at?
: fwohci.c and firewire.c
: printf("non CYCLEMASTER mode\n");
: device_printf(fc->dev, "Initiate bus reset\n");
: Warner> This can't be the case. There's no SPL involved at all. Maybe
: Warner> removing the printfs causes an interrupt to be serviced faster,
: Warner> resulting in what appears to be better performance...
: With the printfs, Ethernet is not getting serviced. This
: is repeatable and easily reproduced. Without the printfs,
: it seems ok.
: If it isn't spl, what is locking out Ethernet?
interrupt storm? In old-spl-locked drivers, often times the interrupt
would be masked while certain operations happened. In new
mutex-locked freebsd, there's no way to block the interrupts, so
sometimes old code gets into an interrupt storm, which starves other
things. Not sure why printf would trigger this, however...
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