Date: Wed, 19 Jul 2006 17:06:43 +0300 From: "victor cruceru" <victor.cruceru@gmail.com> To: freebsd-hackers@freebsd.org Subject: Re: "swiN: clock sio" process taking 75% CPU Message-ID: <49402550607190706q6548ebe7lb9c4dd1ff66b3f1@mail.gmail.com>
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Hi Gareth, Did you try to disable the console screensaver? Sometimes this helps. > Message: 1 > Date: Tue, 18 Jul 2006 13:17:32 +0100 > From: Gareth McCaughan <gmccaughan@synaptics-uk.com> > Subject: "swiN: clock sio" process taking 75% CPU > To: freebsd-hackers@freebsd.org > Message-ID: <200607181317.33416.gmccaughan@synaptics-uk.com> > Content-Type: text/plain; charset="us-ascii" > > (I've asked this question on -questions and -stable, with no success; > hence I'm taking it to the assembled wizardry of -hackers. A bit of > googling suggests that I'm far from the first person to have had a > similar problem, though it seems to be worse for me than for the > others I've found.) > > I have a box running 6-STABLE, cvsupped last week. > Until recently it was running 5.something and showed > the same peculiar behaviour as I'm about to describe. > Further back, it used to run 4.x, and I don't recall > anything like this happening then. > > About 6 minutes after booting (on three occasions, but I > don't guarantee this doesn't vary), a process (well, a > kernel interrupt thread, I guess) that appears in the > output of "ps" as "[swi4: clock sio]" begins to use > about 3/4 of the machine's CPU. I think it does so > more or less instantaneously. It continues to do so > indefinitely, so far as I can tell. > > I'm not aware of anything specific that triggers this, > though I suppose there must *be* something. It happens > apparently spontaneously, on a lightly loaded machine. > > Those cycles are genuinely being consumed; other processes > run much more slowly than they "should", and take much more > wall time than CPU time. > > I've tried diddling my kernel's HZ value; the behaviour > with HZ=100 and with HZ=1000 is the same, so far as I'm > able to tell. I've no idea whether it might be relevant, > but I have option DEVICE_POLLING turned on; toggling > sysctl kern.polling.enable doesn't seem to make any > difference. > > The machine is a very uninteresting single-CPU Athlon box, > clocked at 1.6GHz, several years old. Here's its dmesg output, > with a few uninteresting bits of information leakage elided. > -- victor cruceru ------------------------------------------------ Non est respondendum ad omnia. ( Cicero, Pro Murena Oratio ) ------------------------------------------------
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