Date: Mon, 4 Feb 2008 09:00:54 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-acpi@freebsd.org Cc: Tech Lab Manager <tech@liveoaksf.org> Subject: Re: SMP, ACPI and interrupt storm Message-ID: <200802040900.54630.jhb@freebsd.org> In-Reply-To: <8EE3D963-E390-4F45-A1D1-2295C1767B80@liveoaksf.org> References: <429F40B0-20EE-4F47-847A-A6B1E91BA79F@liveoaksf.org> <47A217FC.1080606@root.org> <8EE3D963-E390-4F45-A1D1-2295C1767B80@liveoaksf.org>
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On Thursday 31 January 2008 02:35:52 pm Tech Lab Manager wrote:
> On Jan 31, 2008, at 10:48 AM, Nate Lawson wrote:
>
> > Tech Lab Manager wrote:
> >> Sorry for the cross-post from freebsd-smb.
> >> Building 6.3-RELEASE and 7.0-RC1 on dual Xeon (4 CPU) boxes:
> >> options SMP
> >> device apic
> >> SMP kernel builds fine, all 4 CPUs launch on reboot.
> >> But I get a TON of interrupts from acpi0 -- about 67,000 per second
> >> according to vmstat -i. With system at idle and almost no services
> >> running, here is output of top -S:
> >> last pid: 877; load averages: 1.18, 0.48, 0.19
> >> 75 processes: 6 running, 54 sleeping, 15 waiting
> >> CPU states: 0.0% user, 0.0% nice, 0.2% system, 22.4%
> >> interrupt, 77.4% idle
> >> Mem: 31M Active, 12M Inact, 28M Wired, 16K Cache, 15M Buf, 3822M Free
> >> Swap: 4096M Total, 4096M Free
> >> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU
> >> COMMAND
> >> 10 root 1 171 52 0K 8K RUN 3 1:11 99.18%
> >> idle: cpu3
> >> 13 root 1 171 52 0K 8K CPU0 0 1:10 98.88%
> >> idle: cpu0
> >> 12 root 1 171 52 0K 8K CPU1 1 1:09 98.78%
> >> idle: cpu1
> >> 21 root 1 -52 -171 0K 8K CPU2 2 0:54 87.24%
> >> irq9: acpi0
> >> 11 root 1 171 52 0K 8K RUN 2 0:17 11.19%
> >> idle: cpu2
> >> Notice high load and interrupt % of CPU.
> >> If turn off ACPI (e.g. set hint.apic.0.disabled=1 in /boot/
> >> loader.conf),
> >> the interrupt storm ceases, but then I'm only running on one CPU.
> >
> > That doesn't turn off acpi, that turns of the APIC (interrupt
> > controller). Try:
> > hint.acpi.0.disabled=1
>
> Sorry, my mistake in writing ACPI above -- I *was* trying to turn off
> apic, based on a note in the FreeBSD handbook.
>
> Disabling ACPI as you suggest above has the same effect as turning
> off APIC: the interrupt storm is disabled but only one CPU is launched.
>
> >
> >> The BIOS ACPI settings are all Enabled. Hyperthreading is Enabled.
> >> These machines have been running RedHat Enterprise 5.0 with full
> >> multiprocessor support.
> >
> > This looks like a failure to sleep in C1 (hlt). Someone else
> > reported this probably earlier, but all debugging showed the
> > inexplicable -- the HLT instruction was being executed but just did
> > not work (returned immediately).
> >
> > There will be a new 7.0 build that fixes one interrupt storm
> > related to level-triggered GPEs. If you can cvsup your 7.0 branch
> > (RELENG_7_0) and retry, that might be helpful to see if it also
> > fixes your problem.
>
> okay, I'm on RC1, will switch to RELENG and report back.
>
> I'm not sure if this is a red herring, but acpidump -t reports:
>
> Type=INT Override
> BUS=0
> IRQ=0
> INTR=2
> Flags={Polarity=conforming, Trigger=conforming}
>
> which looks wrong on several counts (IRQ, INTR should be 9,
> Trigger=level). dmesg even says:
> "MADT: Forcing active-low polarity and level trigger for SCI"
No, this is an entry for something other than the SCI. You can have multiple
interrupt override entries and this entry is typical on all x86 systems with
APICs (the 8259As are tied into pin 0 as a daisy chain and IRQ0 is tied into
intpin 2 since IRQ2 isn't usable with 8259As. Do you have an entry at all
for IRQ 9? If not, then the hw.acpi.sci tunables currently won't do anything
(I can fix it so that they do, however).
--
John Baldwin
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