Re: unusually high load averages

On Jan 29, 2004, at 2:43 PM, Jonathan Fosburgh wrote:

> On Thursday 29 January 2004 03:34 pm, Jake Khuon wrote:
>> I'm noticing some unusually high load averages even though nothing  
>> seems to
>> be taking up much CPU.  This started happening with a recent cvsup  
>> (last
>> night).  Anyone know what might be causing this?
>>
>
> Run `top` and see what your interrupts are doing. I'd guess you're  
> suffering
> from the IRQ20 storm.  vmstat -i should also tell you that.  A patch  
> was
> posted to this list in the last couple of weeks that deals with this.   
> It is
> working for me (I first ran into this a couple of days ago).

   Hello,

   I just moved to a cvsupped 5.2-CURRENT from last night and turned on  
SCHED_ULE, and I am seeing abnormally high load averages too, however  
it does not seem to have anything to do with IRQ 20 (indeed, IRQ20  
isn't even listed in vmstat -i output).

   My system is completely idle and I am seeing:

load averages:  0.92,  0.62,  0.41
33 processes:  1 running, 32 sleeping
CPU states:  0.4% user,  0.0% nice,  0.4% system,  0.9% interrupt,  
98.3% idle

   and top doesn't show any process or system task using >0.00% CPU.   
What's interesting is that this 'ambient load average' seems to be  
trending upwards slowly - when I checked in on it earlier it was more  
like 0.50, 0.35, 0.20.  From sample to sample though there seems to be  
a fair amount of random jitter and it will go up by .2 between one  
sample and the next only to go back down by .3 at the next sample.

   For reference, vmstat -i and dmesg output included.  Let me know if  
there is anything else I can do to help.

interrupt                          total       rate
irq0: clk                         154550         99
irq1: atkbd0                           1          0
irq6: fdc0                             2          0
irq8: rtc                         197835        127
irq9: dc1                          48209         31
irq12: dc0                         55749         36
irq13: npx0                            1          0
irq14: ata0                         1886          1
Total                             458233        296

Copyright (c) 1992-2004 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
         The Regents of the University of California. All rights  
reserved.
FreeBSD 5.2-CURRENT #0: Thu Jan 29 23:47:40 MST 2004
      
sdyoung_at_h68-144-59-39.cg.shawcable.net:/usr/src/sys/i386/compile/ 
CITADEL
Preloaded elf kernel "/boot/kernel/kernel" at 0xc077c000.
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Pentium II/Pentium II Xeon/Celeron (300.68-MHz 686-class CPU)
   Origin = "GenuineIntel"  Id = 0x660  Stepping = 0
    
Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,C 
MOV,PAT,PSE36,MMX,FXSR>
real memory  = 134217728 (128 MB)
avail memory = 125870080 (120 MB)
Pentium Pro MTRR support enabled
npx0: [FAST]
npx0: <math processor> on motherboard
npx0: INT 16 interface
pcibios: BIOS version 2.10
Using $PIR table, 7 entries at 0xc00fdd40
pcib0: <Intel 82443BX (440 BX) host to PCI bridge> at pcibus 0 on  
motherboard
pci0: <PCI bus> on pcib0
pci_cfgintr: 0:7 INTD BIOS irq 10
pci_cfgintr: 0:9 INTA BIOS irq 12
pci_cfgintr: 0:10 INTA BIOS irq 9
agp0: <Intel 82443BX (440 BX) host to PCI bridge> mem  
0xe0000000-0xe3ffffff at device 0.0 on pci0
pcib1: <PCI-PCI bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib1
pci1: <display, VGA> at device 0.0 (no driver attached)
isab0: <PCI-ISA bridge> at device 7.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX4 UDMA33 controller> port 0xf000-0xf00f at device  
7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
ata0: [MPSAFE]
ata1: at 0x170 irq 15 on atapci0
ata1: [MPSAFE]
uhci0: <Intel 82371AB/EB (PIIX4) USB controller> port 0xe000-0xe01f irq  
10 at device 7.2 on pci0
usb0: <Intel 82371AB/EB (PIIX4) USB controller> on uhci0
usb0: USB revision 1.0
uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered
pci0: <bridge, PCI-unknown> at device 7.3 (no driver attached)
dc0: <ADMtek AN985 10/100BaseTX> port 0xe400-0xe4ff mem  
0xe9001000-0xe90013ff irq 12 at device 9.0 on pci0
dc0: Ethernet address: 00:50:bf:ec:65:78
miibus0: <MII bus> on dc0
ukphy0: <Generic IEEE 802.3u media interface> on miibus0
ukphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
dc1: <ADMtek AN985 10/100BaseTX> port 0xe800-0xe8ff mem  
0xe9000000-0xe90003ff irq 9 at device 10.0 on pci0
dc1: Ethernet address: 00:50:bf:ec:5d:4e
miibus1: <MII bus> on dc1
ukphy1: <Generic IEEE 802.3u media interface> on miibus1
ukphy1:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
pmtimer0 on isa0
atkbdc0: <Keyboard controller (i8042)> at port 0x64,0x60 on isa0
atkbd0: <AT Keyboard> flags 0x1 irq 1 on atkbdc0
kbd0 at atkbd0
fdc0: <Enhanced floppy controller (i82077, NE72065 or clone)> at port  
0x3f7,0x3f0-0x3f5 irq 6 drq 2 on isa0
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
ppc0: parallel port not found.
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on  
isa0
unknown: <PNP0303> can't assign resources (port)
unknown: <PNP0a03> can't assign resources (port)
unknown: <PNP0501> can't assign resources (port)
unknown: <PNP0700> can't assign resources (port)
unknown: <PNP0501> can't assign resources (port)
Timecounter "TSC" frequency 300683141 Hz quality 800
Timecounters tick every 10.000 msec
ipfw2 initialized, divert enabled, rule-based forwarding enabled,  
default to deny, logging disabled
ad0: 32253MB <Maxtor 6E040L0> [65531/16/63] at ata0-master UDMA33
Mounting root from ufs:/dev/ad0s1a

   Thanks,
   Steve.