From: Carlos O'Donell <carlos@baldric.uwo.ca>
To: John Marvin <jsm@udlkern.fc.hp.com>
Cc: parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] ksoftirqd eats 100% cpu :-(
Date: Tue, 8 Oct 2002 19:48:54 -0400 [thread overview]
Message-ID: <20021008234854.GE18202@systemhalted> (raw)
In-Reply-To: <200210081427.IAA27522@udlkern.fc.hp.com>
>
> > It's a bug/feature related to the HIL drivers.
> > Since we have to poll the HIL ports the whole time
> > the bunch of running timers increase the ksoftirqd load a lot.
>
> I understand that polling is necessary while sending commands out
> to hil devices, but input should be interrupt driven. What is the
> reason for all of the polling?
>
> John Marvin
> jsm@fc.hp.com
It's interrupt driven, but the ISR _always_ calls tasklet_schedule
to do the real work. The HIL state machine and SERIO layer hooks
in a function to it's own tasklet so it can update on interrupt.
Most drivers usage of tasklets involves:
a- Setup and enable during module init
b- Leave them alone.
I assume that this is the case, because tasklets are CPU intensive.
It would be nice to have someone investiage this... if not, it goes
on the end of my now _really_ long todo list :)
c.
next prev parent reply other threads:[~2002-10-08 23:58 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-08 14:27 [parisc-linux] ksoftirqd eats 100% cpu :-( John Marvin
2002-10-08 23:48 ` Carlos O'Donell [this message]
2002-10-11 8:21 ` Tilo Riemer
2002-10-11 17:13 ` Helge Deller
2002-10-09 3:46 ` Brian S. Julin
2002-10-09 7:41 ` Enrik Berkhan
-- strict thread matches above, loose matches on Subject: below --
2002-10-07 15:23 Tilo Riemer
2002-10-07 15:20 ` Thibaut VARENE
2002-10-07 19:52 ` Helge Deller
2002-10-08 7:59 ` Tilo Riemer
2002-10-08 8:03 ` Tilo Riemer
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