Re: V7 High CPU Usage on swi5:+, what is this process?

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?

Robert N M Watson
Computer Laboratory
University of Cambridge
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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
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