Subject: Re: i386 interrupt counters
To: Noriyuki Soda <soda@sra.co.jp>
From: Michael Graff <explorer@flame.org>
List: tech-kern
Date: 08/12/1996 16:21:01
Noriyuki Soda <soda@sra.co.jp> writes:

> 	each 'com':	In this case, driver level accounting is needed,
> 			and it is not in my scope.
> 	each 'card':	accounting on "struct intrhand" can cope with this.
> 	each IRQ:	old style counter is needed.
> 
> > So, in my opinion, the "Right" thing to do is fix evcnt interrupt
> > counters to be more useful, and, failing that, just use old-style
> > counters.
> 
> How about using both evcnt (per intrhand) and old-style counter (per line) ?

I think you see an implied tree structure here, where the tree looks like

	IRQ0
		card0
			com0
			com1
		card1
			com2
			com3

And this is not the case.  Suppose each com? received 100 interrupts.  The
user would see:

IRQ0	400
card0	200
com0	100
com1	100
card1	200
com2	100
com3	100
TOTAL	1200

Which isn't right at all, since there were only 400 real interrupts.

Even if the IRQ0 were not calculated into this, and old-style and evntcnt
were tallied separately it still won't be right.

--Michael