Date: Fri, 15 Nov 1996 12:45:06 +0100 (MET) From: hm@kts.org (Hellmuth Michaelis) To: msmith@atrad.adelaide.edu.au (Michael Smith) Cc: hm@kts.org, kelly@fsl.noaa.gov, mark@quickweb.com, hackers@FreeBSD.org, current@FreeBSD.org Subject: Re: userland PPP giving weird load numbers Message-ID: <m0vOMhn-00001bC@ernie.kts.org> In-Reply-To: <199611150756.SAA06861@genesis.atrad.adelaide.edu.au> from "Michael Smith" at Nov 15, 96 06:26:01 pm
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> > > I see this too all the time, from 2.0.5 all the way to 2.1.5. While
> > > /usr/sbin/ppp is running, the load average hangs around 1.0. Sometimes,
> > > it'll drop. It's odd ... it's usually when ppp is idle that it hangs
> > > around 1.0.
> >
> > I had this phenomenon too - but NOT with ppp. An isdn userland daemon i am
> > working on showed this exact behaviour; when it was running, the system load
> > was constantly 1.0 or very nearby. This all is under 2.1.5 (and 2.1 too).
> > The process wasn't doing anything (or very little).
>
> But what _was_ it supposed to be doing?
Ok, when this happened, the daemon was in a tight read() loop, where the
read() timed out every second in the driver. Basically after implementing
select() in the driver and using that with a one second timeout made the
problem go away.
In the whole application several one second timeouts exists at several
drivers in the kernel - i'm quite shure there is a problem with something
like several timeouts timing out simultaneously causing something.
I just ran out of ideas where to search for and what to search for so i
stopped looking for the real problem. But i'm able to reproduce it.
hellmuth
--
Hellmuth Michaelis hm@kts.org Hamburg, Europe
(A)bort, (R)etry, (I)nstall BSD ?
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