Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 22 Mar 1995 01:25:09 +1000
From:      Bruce Evans <bde@zeta.org.au>
To:        bde@zeta.org.au, current@FreeBSD.org, se@MI.Uni-Koeln.DE
Subject:   Re: Sharing interrupts with PCI devices?
Message-ID:  <199503211525.BAA19070@godzilla.zeta.org.au>

next in thread | raw e-mail | index | archive | help
>Hmm, you are talking about the overhead
>of returning a '0' or '1' ?
>That's just one or two cycles ...

One or two here, one or two there ...  I'm
looking at a cyclades intelligent serial
board and driver that is 25% slower than
an unintelligent 16450 board and 3 times
slower than an unintelligent 16550 board.
Perhaps it would be faster if cycles weren't
wasted here and there.

>ONLY devices that will be used with shared ints
>have to return some value. In fact, this could

And those handlers that are declared to return
int :-).  I'm more concerned about software
complications and kludges involved in having
only some handlers return int.

>There will be a new function to register a 
>(possibly) shared interrupt.

I think there should be separate interrupt
registration and dispatch, etc. for different
classes of interrupts.  I can save a few usec
in the ISA handlers if they spec'ed to not
support level triggered interrupts.

Bruce



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199503211525.BAA19070>