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From: John Baldwin <jhb@freebsd.org>
To: Robert Watson <rwatson@freebsd.org>
Date: Tue, 18 Mar 2008 09:23:12 -0400
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Cc: freebsd-performance@freebsd.org, Aminuddin Abdullah <amin.scg@gmail.com>
Subject: Re: V7 High CPU Usage on swi5:+, what is this process?
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On Tuesday 18 March 2008 09:04:05 am Robert Watson wrote:
> On Tue, 18 Mar 2008, John Baldwin wrote:
> >> '+' is used in a swi name to indicate that the names of the interrupts
> >> to put in the thread name are too long, and the code looks like it was
> >> written under the assumption that at least one name would fit.  It
> >> sounds like in this case, none fit.  We should fix this code, but in the
> >> mean time, what you might consider doing is hacking intr_event_update()
> >> in kern_intr.c to print out overflowing names to the console using
> >> printf(9) so you can at least see what they are.  This is the somewhat
> >> suspect bit of code:
> >
> > The code is not suspect as p_comm is of fixed length.  Someone just used
> > too long of a name for a swi handler.
>
> I was wondering whether we might not do better to put as much in as we can
> but truncate with a '*', so you at least get a fractional swi name.  Under
> what situations do we use a single ithread for multiple swi's?

The softclock one gets overloaded with some tty handlers.  This code is also 
just generic ithread code common to swi's and hardware interrupts.

-- 
John Baldwin