# top reports cpu 100% wait but no process that uses it

## no_hope

I am on an core 2 system and I've noticed that often one of the cores spends almost all its time in io wait even though no process appears to be using it.

That is, top's CpuX row shows near 100% wait (or split 50-50 between cores) but shows no process that is causing that. The %CPU column either all 0s or some low values. Performance doesn't seem to be affected too much, but X feels sluggish.

The only slightly unusual thing about my system is that it has 5GB or ram. That causes pdfulsh to go haywire every once in a while, but "echo 1 > /proc/sys/vm/drop_caches" solves that problem, but appears to have no effect on the problem I'm describing.

This has been going on for quite a while now. Any idea what it could be?

```
Portage 2.1.3.19 (default-linux/amd64/2007.0, gcc-4.1.2, glibc-2.6.1-r0, 2.6.24-rc2 x86_64)

=================================================================

System uname: 2.6.24-rc2 x86_64 Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz

Timestamp of tree: Thu, 08 Nov 2007 22:16:01 +0000

app-shells/bash:     3.2_p17

dev-java/java-config: 1.3.7, 2.0.33-r1

dev-lang/python:     2.4.4-r5, 2.5.1-r3

sys-apps/baselayout: 1.12.9-r2

sys-apps/sandbox:    1.2.18.1-r2

sys-devel/autoconf:  2.13, 2.61-r1

sys-devel/automake:  1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10

sys-devel/binutils:  2.18-r1

sys-devel/gcc-config: 1.3.16

sys-devel/libtool:   1.5.24

virtual/os-headers:  2.6.22-r2

ACCEPT_KEYWORDS="amd64"

CBUILD="x86_64-pc-linux-gnu"

CFLAGS="-march=nocona -O2 -pipe -ftracer -ftree-vectorize"

CHOST="x86_64-pc-linux-gnu"

CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config"

CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c /etc/udev/rules.d"

CXXFLAGS="-march=nocona -O2 -pipe -ftracer -ftree-vectorize"

DISTDIR="/usr/portage/distfiles"

FEATURES="distlocks metadata-transfer parallel-fetch sandbox sfperms strict unmerge-orphans userfetch"

GENTOO_MIRRORS="http://gentoo.chem.wisc.edu/gentoo"

LINGUAS="en ru"

MAKEOPTS="-j3"

PKGDIR="/usr/portage/packages"

PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*"

PORTAGE_TMPDIR="/var/tmp"

PORTDIR="/usr/portage"

PORTDIR_OVERLAY="/usr/portage/local/layman/sunrise /usr/portage/local/layman/vmware /usr/portage/local/layman/kde /usr/portage/local/layman/science /usr/portage/local/usr /usr/portage/local/mozilla"

SYNC="rsync://gentoo3.chem.wisc.edu/gentoo-portage"

USE="X acpi alsa amd64 arts berkdb bitmap-fonts bzip2 cairo cli cracklib cups dbus dri fortran gdbm gimp gnuplot gpm gtk hal iconv imagemagick isdnlog jpeg jpeg2k kde kdeenablefinal kdehiddenvisibility midi mmap mmx mudflap ncurses nptl nptlonly opengl openmp pam pcre pdf perl plotutils png postscript pppd python qt qt3 qt4 readline reflection sdl session smp spl sse sse2 ssl svg threads truetype truetype-fonts type1-fonts usb wmf xcb xinerama xorg xscreensaver zlib" ALSA_CARDS="hda-intel" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="en ru" USERLAND="GNU" VIDEO_CARDS="nvidia"

Unset:  CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS
```

```
00:00.0 Host bridge: Intel Corporation 82P965/G965 Memory Controller Hub (rev 02)

00:01.0 PCI bridge: Intel Corporation 82P965/G965 PCI Express Root Port (rev 02)

00:03.0 Communication controller: Intel Corporation 82P965/G965 HECI Controller (rev 02)

00:1a.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Contoller #4 (rev 02)

00:1a.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #5 (rev 02)

00:1a.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #2 (rev 02)

00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 02)

00:1c.0 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 (rev 02)

00:1c.3 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 4 (rev 02)

00:1c.4 PCI bridge: Intel Corporation 82801H (ICH8 Family) PCI Express Port 5 (rev 02)

00:1d.0 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #1 (rev 02)

00:1d.1 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #2 (rev 02)

00:1d.2 USB Controller: Intel Corporation 82801H (ICH8 Family) USB UHCI Controller #3 (rev 02)

00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 02)

00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev f2)

00:1f.0 ISA bridge: Intel Corporation 82801HB/HR (ICH8/R) LPC Interface Controller (rev 02)

00:1f.2 SATA controller: Intel Corporation 82801HB (ICH8) 4 port SATA AHCI Controller (rev 02)

00:1f.3 SMBus: Intel Corporation 82801H (ICH8 Family) SMBus Controller (rev 02)

01:00.0 VGA compatible controller: nVidia Corporation G70 [GeForce 7600 GT] (rev a1)

03:00.0 SATA controller: JMicron Technologies, Inc. JMicron 20360/20363 AHCI Controller (rev 02)

03:00.1 IDE interface: JMicron Technologies, Inc. JMicron 20360/20363 AHCI Controller (rev 02)

04:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053 PCI-E Gigabit Ethernet Controller (rev 22)

05:02.0 VGA compatible controller: nVidia Corporation NV44A [GeForce 6200] (rev a1)
```

```
aces ~ # cat /proc/sys/vm/dirty_background_ratio

5

aces ~ # cat /proc/sys/vm/dirty_ratio

10

```

```
Linux version 2.6.24-rc2 (root@aces) (gcc version 4.1.2 (Gentoo 4.1.2 p1.0.2)) #2 SMP Wed Nov 7 19:39:07 CST 2007

Command line: root=/dev/sda2 agp=off

BIOS-provided physical RAM map:

 BIOS-e820: 0000000000000000 - 000000000009e800 (usable)

 BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)

 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)

 BIOS-e820: 0000000000100000 - 00000000cfee0000 (usable)

 BIOS-e820: 00000000cfee0000 - 00000000cfee3000 (ACPI NVS)

 BIOS-e820: 00000000cfee3000 - 00000000cfef0000 (ACPI data)

 BIOS-e820: 00000000cfef0000 - 00000000cff00000 (reserved)

 BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)

 BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)

 BIOS-e820: 0000000100000000 - 0000000168000000 (usable)

Entering add_active_range(0, 0, 158) 0 entries of 256 used

Entering add_active_range(0, 256, 851680) 1 entries of 256 used

Entering add_active_range(0, 1048576, 1474560) 2 entries of 256 used

end_pfn_map = 1474560

DMI 2.4 present.

ACPI: RSDP 000F6CF0, 0014 (r0 GBT   )

ACPI: RSDT CFEE3040, 003C (r1 GBT    GBTUACPI 42302E31 GBTU  1010101)

ACPI: FACP CFEE30C0, 0074 (r1 GBT    GBTUACPI 42302E31 GBTU  1010101)

ACPI: DSDT CFEE3180, 49F4 (r1 GBT    GBTUACPI     1000 MSFT  100000C)

ACPI: FACS CFEE0000, 0040

ACPI: HPET CFEE7CC0, 0038 (r1 GBT    GBTUACPI 42302E31 GBTU       98)

ACPI: MCFG CFEE7D40, 003C (r1 GBT    GBTUACPI 42302E31 GBTU  1010101)

ACPI: APIC CFEE7BC0, 0084 (r1 GBT    GBTUACPI 42302E31 GBTU  1010101)

ACPI: SSDT CFEE7DC0, 015C (r1  PmRef  Cpu0Ist     3000 INTL 20040311)

ACPI: SSDT CFEE8250, 0275 (r1  PmRef    CpuPm     3000 INTL 20040311)

Entering add_active_range(0, 0, 158) 0 entries of 256 used

Entering add_active_range(0, 256, 851680) 1 entries of 256 used

Entering add_active_range(0, 1048576, 1474560) 2 entries of 256 used

Zone PFN ranges:

  DMA             0 ->     4096

  DMA32        4096 ->  1048576

  Normal    1048576 ->  1474560

Movable zone start PFN for each node

early_node_map[3] active PFN ranges

    0:        0 ->      158

    0:      256 ->   851680

    0:  1048576 ->  1474560

On node 0 totalpages: 1277566

  DMA zone: 56 pages used for memmap

  DMA zone: 1139 pages reserved

  DMA zone: 2803 pages, LIFO batch:0

  DMA32 zone: 14280 pages used for memmap

  DMA32 zone: 833304 pages, LIFO batch:31

  Normal zone: 5824 pages used for memmap

  Normal zone: 420160 pages, LIFO batch:31

  Movable zone: 0 pages used for memmap

ACPI: PM-Timer IO Port: 0x408

ACPI: Local APIC address 0xfee00000

ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)

Processor #0 (Bootup-CPU)

ACPI: LAPIC (acpi_id[0x01] lapic_id[0x01] enabled)

Processor #1

ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] disabled)

ACPI: LAPIC (acpi_id[0x03] lapic_id[0x03] disabled)

ACPI: LAPIC_NMI (acpi_id[0x00] dfl dfl lint[0x1])

ACPI: LAPIC_NMI (acpi_id[0x01] dfl dfl lint[0x1])

ACPI: LAPIC_NMI (acpi_id[0x02] dfl dfl lint[0x1])

ACPI: LAPIC_NMI (acpi_id[0x03] dfl dfl lint[0x1])

ACPI: IOAPIC (id[0x02] address[0xfec00000] gsi_base[0])

IOAPIC[0]: apic_id 2, address 0xfec00000, GSI 0-23

ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)

ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)

ACPI: IRQ0 used by override.

ACPI: IRQ2 used by override.

ACPI: IRQ9 used by override.

Setting APIC routing to flat

ACPI: HPET id: 0x8086a201 base: 0xfed00000

Using ACPI (MADT) for SMP configuration information

Allocating PCI resources starting at d0000000 (gap: cff00000:20100000)

PERCPU: Allocating 31728 bytes of per cpu data

Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 1256267

Kernel command line: root=/dev/sda2 agp=off

Initializing CPU#0

PID hash table entries: 4096 (order: 12, 32768 bytes)

hpet clockevent registered

TSC calibrated against HPET

time.c: Detected 2133.333 MHz processor.

Console: colour VGA+ 80x25

console [tty0] enabled

Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes)

Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes)

Checking aperture...

PCI-DMA: Using software bounce buffering for IO (SWIOTLB)

Placing software IO TLB between 0x6aff000 - 0xaaff000

Memory: 4946324k/5898240k available (2501k kernel code, 163680k reserved, 1312k data, 212k init)

SLUB: Genslabs=11, HWalign=64, Order=0-1, MinObjects=4, CPUs=2, Nodes=1

Calibrating delay using timer specific routine.. 4269.66 BogoMIPS (lpj=8539327)

Mount-cache hash table entries: 256

CPU: L1 I cache: 32K, L1 D cache: 32K

CPU: L2 cache: 2048K

using mwait in idle threads.

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 0

CPU0: Thermal monitoring enabled (TM2)

Freeing SMP alternatives: 25k freed

ACPI: Core revision 20070126

Using local APIC timer interrupts.

APIC timer calibration result 16666660

Detected 16.666 MHz APIC timer.

Booting processor 1/2 APIC 0x1

Initializing CPU#1

Calibrating delay using timer specific routine.. 4266.69 BogoMIPS (lpj=8533384)

CPU: L1 I cache: 32K, L1 D cache: 32K

CPU: L2 cache: 2048K

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 1

CPU1: Thermal monitoring enabled (TM2)

Intel(R) Core(TM)2 CPU          6400  @ 2.13GHz stepping 06

checking TSC synchronization [CPU#0 -> CPU#1]: passed.

Brought up 2 CPUs

net_namespace: 120 bytes

NET: Registered protocol family 16

ACPI: bus type pci registered

PCI: Using MMCONFIG at f0000000 - f3ffffff

mtrr: your CPUs had inconsistent variable MTRR settings

mtrr: probably your BIOS does not setup all CPUs.

mtrr: corrected configuration.

ACPI: EC: Look up EC in DSDT

ACPI: Interpreter enabled

ACPI: (supports S0 S5)

ACPI: Using IOAPIC for interrupt routing

ACPI: PCI Root Bridge [PCI0] (0000:00)

PCI quirk: region 0400-047f claimed by ICH6 ACPI/GPIO/TCO

PCI quirk: region 0480-04bf claimed by ICH6 GPIO

PCI: Transparent bridge - 0000:00:1e.0

ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]

ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.PEX0._PRT]

ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.PEX3._PRT]

ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.PEX4._PRT]

ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.HUB0._PRT]

ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 9 10 11 12 14 *15)

ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 9 10 11 12 14 15) *0, disabled.

ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 9 *10 11 12 14 15)

ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 6 7 9 10 *11 12 14 15)

ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 6 7 9 10 11 12 14 15) *0, disabled.

ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 5 6 *7 9 10 11 12 14 15)

ACPI: PCI Interrupt Link [LNK0] (IRQs 3 4 5 6 7 9 10 11 12 *14 15)

ACPI: PCI Interrupt Link [LNK1] (IRQs 3 4 *5 6 7 9 10 11 12 14 15)

Linux Plug and Play Support v0.97 (c) Adam Belay

pnp: PnP ACPI init

ACPI: bus type pnp registered

pnp: PnP ACPI: found 11 devices

ACPI: ACPI bus type pnp unregistered

SCSI subsystem initialized

libata version 3.00 loaded.

usbcore: registered new interface driver usbfs

usbcore: registered new interface driver hub

usbcore: registered new device driver usb

PCI: Using ACPI for IRQ routing

PCI: If a device doesn't work, try "pci=routeirq".  If it helps, post a report

PCI-GART: No AMD northbridge found.

hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0

hpet0: 3 64-bit timers, 14318180 Hz

ACPI: RTC can wake from S4

Time: tsc clocksource has been installed.

system 00:07: ioport range 0x400-0x4bf could not be reserved

system 00:08: iomem range 0xf0000000-0xf3ffffff could not be reserved

system 00:09: iomem range 0xd5000-0xd7fff has been reserved

system 00:09: iomem range 0xf0000-0xf7fff could not be reserved

system 00:09: iomem range 0xf8000-0xfbfff could not be reserved

system 00:09: iomem range 0xfc000-0xfffff could not be reserved

PCI: Bridge: 0000:00:01.0

  IO window: 8000-8fff

  MEM window: f9000000-fbffffff

  PREFETCH window: d0000000-dfffffff

PCI: Bridge: 0000:00:1c.0

  IO window: 7000-7fff

  MEM window: disabled.

  PREFETCH window: disabled.

PCI: Bridge: 0000:00:1c.3

  IO window: 9000-afff

  MEM window: fc000000-fc0fffff

  PREFETCH window: disabled.

PCI: Bridge: 0000:00:1c.4

  IO window: b000-bfff

  MEM window: f4000000-f5ffffff

  PREFETCH window: disabled.

PCI: Bridge: 0000:00:1e.0

  IO window: disabled.

  MEM window: f6000000-f8ffffff

  PREFETCH window: e0000000-efffffff

ACPI: PCI Interrupt 0000:00:01.0[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:00:01.0 to 64

ACPI: PCI Interrupt 0000:00:1c.0[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:00:1c.0 to 64

ACPI: PCI Interrupt 0000:00:1c.3[D] -> GSI 19 (level, low) -> IRQ 19

PCI: Setting latency timer of device 0000:00:1c.3 to 64

ACPI: PCI Interrupt 0000:00:1c.4[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:00:1c.4 to 64

PCI: Setting latency timer of device 0000:00:1e.0 to 64

NET: Registered protocol family 2

IP route cache hash table entries: 262144 (order: 9, 2097152 bytes)

TCP established hash table entries: 131072 (order: 9, 3145728 bytes)

TCP bind hash table entries: 65536 (order: 8, 1048576 bytes)

TCP: Hash tables configured (established 131072 bind 65536)

TCP reno registered

IA-32 Microcode Update Driver: v1.14a <tigran@aivazian.fsnet.co.uk>

Total HugeTLB memory allocated, 0

io scheduler noop registered

io scheduler deadline registered

io scheduler cfq registered (default)

Boot video device is 0000:01:00.0

PCI: Setting latency timer of device 0000:00:01.0 to 64

assign_interrupt_mode Found MSI capability

Allocate Port Service[0000:00:01.0:pcie00]

Allocate Port Service[0000:00:01.0:pcie03]

PCI: Setting latency timer of device 0000:00:1c.0 to 64

assign_interrupt_mode Found MSI capability

Allocate Port Service[0000:00:1c.0:pcie00]

Allocate Port Service[0000:00:1c.0:pcie02]

Allocate Port Service[0000:00:1c.0:pcie03]

PCI: Setting latency timer of device 0000:00:1c.3 to 64

assign_interrupt_mode Found MSI capability

Allocate Port Service[0000:00:1c.3:pcie00]

Allocate Port Service[0000:00:1c.3:pcie02]

Allocate Port Service[0000:00:1c.3:pcie03]

PCI: Setting latency timer of device 0000:00:1c.4 to 64

assign_interrupt_mode Found MSI capability

Allocate Port Service[0000:00:1c.4:pcie00]

Allocate Port Service[0000:00:1c.4:pcie02]

Allocate Port Service[0000:00:1c.4:pcie03]

ACPI: Processor [CPU0] (supports 2 throttling states)

ACPI: SSDT CFEE81C0, 0087 (r1  PmRef  Cpu1Ist     3000 INTL 20040311)

ACPI: Processor [CPU1] (supports 2 throttling states)

Real Time Clock Driver v1.12ac

Non-volatile memory driver v1.2

Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled

serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

loop: module loaded

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2

ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx

ahci 0000:00:1f.2: version 3.0

ACPI: PCI Interrupt 0000:00:1f.2[B] -> GSI 19 (level, low) -> IRQ 19

Switched to high resolution mode on CPU 1

Switched to high resolution mode on CPU 0

ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0x33 impl SATA mode

ahci 0000:00:1f.2: flags: 64bit ncq sntf stag pm led clo pio slum part

PCI: Setting latency timer of device 0000:00:1f.2 to 64

scsi0 : ahci

scsi1 : ahci

scsi2 : ahci

scsi3 : ahci

scsi4 : ahci

scsi5 : ahci

ata1: SATA max UDMA/133 irq_stat 0x00000040,  irq 315

ata2: SATA max UDMA/133 abar m2048@0xfc107000 port 0xfc107180 irq 315

ata3: DUMMY

ata4: DUMMY

ata5: SATA max UDMA/133 abar m2048@0xfc107000 port 0xfc107300 irq 315

ata6: SATA max UDMA/133 abar m2048@0xfc107000 port 0xfc107380 irq 315

ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)

ata1.00: ATA-7: WDC WD1500AHFD-00RAR1, 20.07P20, max UDMA/133

ata1.00: 293046768 sectors, multi 0: LBA48 NCQ (depth 31/32)

ata1.00: configured for UDMA/133

ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300)

ata2.00: HPA detected: current 312579695, native 312581808

ata2.00: ATA-7: WDC WD1600JS-00NCB1, 10.02E02, max UDMA/133

ata2.00: 312579695 sectors, multi 0: LBA48 NCQ (depth 31/32)

ata2.00: configured for UDMA/133

ata5: SATA link down (SStatus 0 SControl 300)

ata6: SATA link down (SStatus 0 SControl 300)

scsi 0:0:0:0: Direct-Access     ATA      WDC WD1500AHFD-0 20.0 PQ: 0 ANSI: 5

sd 0:0:0:0: [sda] 293046768 512-byte hardware sectors (150040 MB)

sd 0:0:0:0: [sda] Write Protect is off

sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00

sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

sd 0:0:0:0: [sda] 293046768 512-byte hardware sectors (150040 MB)

sd 0:0:0:0: [sda] Write Protect is off

sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00

sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

 sda: sda1 sda2 sda3

sd 0:0:0:0: [sda] Attached SCSI disk

sd 0:0:0:0: Attached scsi generic sg0 type 0

scsi 1:0:0:0: Direct-Access     ATA      WDC WD1600JS-00N 10.0 PQ: 0 ANSI: 5

sd 1:0:0:0: [sdb] 312579695 512-byte hardware sectors (160041 MB)

sd 1:0:0:0: [sdb] Write Protect is off

sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00

sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

sd 1:0:0:0: [sdb] 312579695 512-byte hardware sectors (160041 MB)

sd 1:0:0:0: [sdb] Write Protect is off

sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00

sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

 sdb: sdb1

sd 1:0:0:0: [sdb] Attached SCSI disk

sd 1:0:0:0: Attached scsi generic sg1 type 0

ACPI: PCI Interrupt 0000:03:00.0[A] -> GSI 19 (level, low) -> IRQ 19

ahci 0000:03:00.0: AHCI 0001.0000 32 slots 2 ports 3 Gbps 0x3 impl SATA mode

ahci 0000:03:00.0: flags: 64bit ncq pm led clo pmp pio slum part

PCI: Setting latency timer of device 0000:03:00.0 to 64

scsi6 : ahci

scsi7 : ahci

ata7: SATA max UDMA/133 abar m8192@0xfc000000 port 0xfc000100 irq 19

ata8: SATA max UDMA/133 abar m8192@0xfc000000 port 0xfc000180 irq 19

ata7: SATA link down (SStatus 0 SControl 300)

ata8: SATA link down (SStatus 0 SControl 300)

ACPI: PCI Interrupt 0000:03:00.1[B] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:03:00.1 to 64

scsi8 : pata_jmicron

scsi9 : pata_jmicron

ata9: PATA max UDMA/100 cmd 0x9000 ctl 0x9400 bmdma 0xa000 irq 16

ata10: PATA max UDMA/100 cmd 0x9800 ctl 0x9c00 bmdma 0xa008 irq 16

ata9.01: ATAPI: LITE-ON DVDRW SOHW-1693S, KS06, max UDMA/66

ata9.01: configured for UDMA/66

scsi 8:0:1:0: CD-ROM            LITE-ON  DVDRW SOHW-1693S KS06 PQ: 0 ANSI: 5

sr0: scsi3-mmc drive: 48x/48x writer cd/rw xa/form2 cdda tray

Uniform CD-ROM driver Revision: 3.20

sr 8:0:1:0: Attached scsi CD-ROM sr0

sr 8:0:1:0: Attached scsi generic sg2 type 5

ACPI: PCI Interrupt 0000:00:1a.7[C] -> GSI 18 (level, low) -> IRQ 18

PCI: Setting latency timer of device 0000:00:1a.7 to 64

ehci_hcd 0000:00:1a.7: EHCI Host Controller

ehci_hcd 0000:00:1a.7: new USB bus registered, assigned bus number 1

PCI: cache line size of 32 is not supported by device 0000:00:1a.7

ehci_hcd 0000:00:1a.7: irq 18, io mem 0xfc105000

ehci_hcd 0000:00:1a.7: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004

usb usb1: configuration #1 chosen from 1 choice

hub 1-0:1.0: USB hub found

hub 1-0:1.0: 4 ports detected

ACPI: PCI Interrupt 0000:00:1d.7[A] -> GSI 23 (level, low) -> IRQ 23

PCI: Setting latency timer of device 0000:00:1d.7 to 64

ehci_hcd 0000:00:1d.7: EHCI Host Controller

ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 2

PCI: cache line size of 32 is not supported by device 0000:00:1d.7

ehci_hcd 0000:00:1d.7: irq 23, io mem 0xfc104000

ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004

usb usb2: configuration #1 chosen from 1 choice

hub 2-0:1.0: USB hub found

hub 2-0:1.0: 6 ports detected

USB Universal Host Controller Interface driver v3.0

ACPI: PCI Interrupt 0000:00:1a.0[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:00:1a.0 to 64

uhci_hcd 0000:00:1a.0: UHCI Host Controller

uhci_hcd 0000:00:1a.0: new USB bus registered, assigned bus number 3

uhci_hcd 0000:00:1a.0: irq 16, io base 0x0000c000

usb usb3: configuration #1 chosen from 1 choice

hub 3-0:1.0: USB hub found

hub 3-0:1.0: 2 ports detected

ACPI: PCI Interrupt 0000:00:1a.1[B] -> GSI 21 (level, low) -> IRQ 21

PCI: Setting latency timer of device 0000:00:1a.1 to 64

uhci_hcd 0000:00:1a.1: UHCI Host Controller

uhci_hcd 0000:00:1a.1: new USB bus registered, assigned bus number 4

uhci_hcd 0000:00:1a.1: irq 21, io base 0x0000c400

usb usb4: configuration #1 chosen from 1 choice

hub 4-0:1.0: USB hub found

hub 4-0:1.0: 2 ports detected

ACPI: PCI Interrupt 0000:00:1d.0[A] -> GSI 23 (level, low) -> IRQ 23

PCI: Setting latency timer of device 0000:00:1d.0 to 64

uhci_hcd 0000:00:1d.0: UHCI Host Controller

uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 5

uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000c800

usb usb5: configuration #1 chosen from 1 choice

hub 5-0:1.0: USB hub found

hub 5-0:1.0: 2 ports detected

usb 2-5: new high speed USB device using ehci_hcd and address 2

ACPI: PCI Interrupt 0000:00:1d.1[B] -> GSI 19 (level, low) -> IRQ 19

PCI: Setting latency timer of device 0000:00:1d.1 to 64

uhci_hcd 0000:00:1d.1: UHCI Host Controller

uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 6

uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000cc00

usb usb6: configuration #1 chosen from 1 choice

hub 6-0:1.0: USB hub found

hub 6-0:1.0: 2 ports detected

usb 2-5: configuration #1 chosen from 1 choice

hub 2-5:1.0: USB hub found

hub 2-5:1.0: 4 ports detected

ACPI: PCI Interrupt 0000:00:1d.2[C] -> GSI 18 (level, low) -> IRQ 18

PCI: Setting latency timer of device 0000:00:1d.2 to 64

uhci_hcd 0000:00:1d.2: UHCI Host Controller

uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 7

uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000d000

usb usb7: configuration #1 chosen from 1 choice

hub 7-0:1.0: USB hub found

hub 7-0:1.0: 2 ports detected

Initializing USB Mass Storage driver...

usb 2-5.1: new high speed USB device using ehci_hcd and address 3

usb 2-5.1: configuration #1 chosen from 1 choice

hub 2-5.1:1.0: USB hub found

hub 2-5.1:1.0: 4 ports detected

usb 2-5.2: new low speed USB device using ehci_hcd and address 4

usb 2-5.2: configuration #1 chosen from 1 choice

usb 2-5.3: new low speed USB device using ehci_hcd and address 5

usb 2-5.3: configuration #1 chosen from 1 choice

usb 2-5.1.1: new low speed USB device using ehci_hcd and address 6

usb 2-5.1.1: configuration #1 chosen from 1 choice

usbcore: registered new interface driver usb-storage

USB Mass Storage support registered.

PNP: No PS/2 controller found. Probing ports directly.

serio: i8042 KBD port at 0x60,0x64 irq 1

serio: i8042 AUX port at 0x60,0x64 irq 12

mice: PS/2 mouse device common for all mice

input: PC Speaker as /class/input/input0

i2c /dev entries driver

ACPI: PCI Interrupt 0000:00:1f.3[C] -> GSI 18 (level, low) -> IRQ 18

coretemp coretemp.0: Using undocumented features, absolute temperature might be wrong!

coretemp coretemp.1: Using undocumented features, absolute temperature might be wrong!

it87: Found IT8718F chip at 0x290, revision 1

it87: in3 is VCC (+5V)

input: Logitech USB Receiver as /class/input/input1

input: USB HID v1.11 Mouse [Logitech USB Receiver] on usb-0000:00:1d.7-5.2

input: Microsoft Natural® Ergonomic Keyboard 4000 as /class/input/input2

input: USB HID v1.11 Keyboard [Microsoft Natural® Ergonomic Keyboard 4000] on usb-0000:00:1d.7-5.3

input: Microsoft Natural® Ergonomic Keyboard 4000 as /class/input/input3

input: USB HID v1.11 Device [Microsoft Natural® Ergonomic Keyboard 4000] on usb-0000:00:1d.7-5.3

input: Microsoft Basic Optical Mouse as /class/input/input4

input: USB HID v1.10 Mouse [Microsoft Basic Optical Mouse] on usb-0000:00:1d.7-5.1.1

usbcore: registered new interface driver usbhid

drivers/hid/usbhid/hid-core.c: v2.6:USB HID core driver

Advanced Linux Sound Architecture Driver Version 1.0.15 (Tue Oct 23 06:09:18 2007 UTC).

ACPI: PCI Interrupt 0000:00:1b.0[A] -> GSI 22 (level, low) -> IRQ 22

PCI: Setting latency timer of device 0000:00:1b.0 to 64

ALSA device list:

  #0: HDA Intel at 0xfc100000 irq 22

TCP cubic registered

NET: Registered protocol family 1

NET: Registered protocol family 17

drivers/rtc/hctosys.c: unable to open rtc device (rtc0)

ReiserFS: sda2: found reiserfs format "3.6" with standard journal

ReiserFS: sda2: using ordered data mode

ReiserFS: sda2: journal params: device sda2, size 8192, journal first block 18, max trans len 1024, max batch 900, max commit age 30, max trans age 30

ReiserFS: sda2: checking transaction log (sda2)

ReiserFS: sda2: replayed 103 transactions in 11 seconds

ReiserFS: sda2: Using r5 hash to sort names

VFS: Mounted root (reiserfs filesystem) readonly.

Freeing unused kernel memory: 212k freed

ACPI: PCI Interrupt 0000:04:00.0[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:04:00.0 to 64

sky2 0000:04:00.0: v1.19 addr 0xf5000000 irq 16 Yukon-EC (0xb6) rev 2

sky2 eth0: addr 00:16:e6:80:e1:13

nvidia: module license 'NVIDIA' taints kernel.

ACPI: PCI Interrupt 0000:01:00.0[A] -> GSI 16 (level, low) -> IRQ 16

PCI: Setting latency timer of device 0000:01:00.0 to 64

PCI: Enabling device 0000:05:02.0 (0000 -> 0002)

ACPI: PCI Interrupt 0000:05:02.0[A] -> GSI 18 (level, low) -> IRQ 18

NVRM: loading NVIDIA UNIX x86_64 Kernel Module  100.14.19  Wed Sep 12 14:08:38 PDT 2007

ReiserFS: sda2: switching to writeback data mode

ReiserFS: sda2: Removing [291 5741627 0x0 SD]..done

ReiserFS: sda2: Removing [5734259 5734263 0x0 SD]..done

ReiserFS: sda2: Removing [5734259 5734261 0x0 SD]..done

ReiserFS: sda2: Removing [5734253 5734255 0x0 SD]..done

ReiserFS: sda2: Removing [5734244 5734245 0x0 SD]..done

ReiserFS: sda2: Removing [5734228 5734234 0x0 SD]..done

ReiserFS: sda2: Removing [5732888 5732889 0x0 SD]..done

ReiserFS: sda2: Removing [5732887 5732888 0x0 SD]..done

ReiserFS: sda2: Removing [5732857 5732887 0x0 SD]..done

ReiserFS: sda2: Removing [5732813 5732857 0x0 SD]..done

ReiserFS: sda2: Removing [5730968 5732813 0x0 SD]..done

ReiserFS: sda2: Removing [1925558 5731828 0x0 SD]..done

ReiserFS: sda2: Removing [655325 5730968 0x0 SD]..done

ReiserFS: sda2: Removing [251468 5343718 0x0 SD]..done

ReiserFS: sda2: Removing [251468 5343601 0x0 SD]..done

ReiserFS: sda2: Removing [251468 5343577 0x0 SD]..done

ReiserFS: sda2: Removing [293 3679480 0x0 SD]..done

ReiserFS: sda2: Removing [291 3532349 0x0 SD]..done

ReiserFS: sda2: Removing [291 2061154 0x0 SD]..done

ReiserFS: sda2: Removing [291 666876 0x0 SD]..done

ReiserFS: sda2: Removing [5731828 655325 0x0 SD]..done

ReiserFS: sda2: Removing [291 243383 0x0 SD]..done

ReiserFS: sda2: Removing [291 26545 0x0 SD]..done

ReiserFS: sda2: There were 23 uncompleted unlinks/truncates. Completed

ReiserFS: sdb1: found reiserfs format "3.6" with standard journal

ReiserFS: sdb1: using writeback data mode

ReiserFS: sdb1: journal params: device sdb1, size 8192, journal first block 18, max trans len 1024, max batch 900, max commit age 30, max trans age 30

ReiserFS: sdb1: checking transaction log (sdb1)

ReiserFS: sdb1: replayed 38 transactions in 4 seconds

ReiserFS: sdb1: Using r5 hash to sort names

Adding 8779512k swap on /dev/sda3.  Priority:-1 extents:1 across:8779512k

sky2 eth0: enabling interface

sky2 eth0: Link is up at 100 Mbps, full duplex, flow control both

```

```

           CPU0       CPU1

  0:        335          0   IO-APIC-edge      timer

  1:          2          0   IO-APIC-edge      i8042

  4:          2          0   IO-APIC-edge

  8:          1          0   IO-APIC-edge      rtc

  9:          0          0   IO-APIC-fasteoi   acpi

 12:          4          0   IO-APIC-edge      i8042

 16:    7122671          0   IO-APIC-fasteoi   libata, uhci_hcd:usb3, nvidia

 18:    3120704          0   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb7, nvidia

 19:          0          0   IO-APIC-fasteoi   ahci, uhci_hcd:usb6

 21:          0          0   IO-APIC-fasteoi   uhci_hcd:usb4

 22:     559248          0   IO-APIC-fasteoi   HDA Intel

 23:     769043          0   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb5

314:    2611013          0   PCI-MSI-edge      eth0

315:     585740          0   PCI-MSI-edge      ahci

NMI:          0          0   Non-maskable interrupts

LOC:   22290488   22332234   Local timer interrupts

RES:      49239     110901   Rescheduling interrupts

CAL:      11293      26190   function call interrupts

TLB:      42119      45554   TLB shootdowns

TRM:          0          0   Thermal event interrupts

THR:          0          0   Threshold APIC interrupts

SPU:          0          0   Spurious interrupts

ERR:          0
```

----------

## HeissFuss

You should look for processes with state D from top or ps aux.

Other things to check:

Is the system paging/disks being hit hard.

Are their a lot of network connections/network IO.

----------

## baeksu

Does top show kernel processes? I had some problem earlier where some kernel process would peg one core to 100% after a suspend/resume cycle, but I didn't see it at first because my top configuration didn't show kernel processes.

----------

## no_hope

 *HeissFuss wrote:*   

> You should look for processes with state D from top or ps aux.
> 
> Other things to check:
> 
> Is the system paging/disks being hit hard.
> ...

 

The issue happens when the machine is completely idle -- only X and top are running, no network, no disk activity.

```
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND

root     26355  0.1  0.0      0     0 ?        D    Nov08   0:47 [pdflush]
```

```
aces ~ # free

             total       used       free     shared    buffers     cached

Mem:       4946824    1686328    3260496          0      14024     103984

-/+ buffers/cache:    1568320    3378504

Swap:      8779512        376    8779136
```

What the hell is is doing though? If I drop caches it stops running for a little while but the starts again even if I don't really do anything.

----------

## salahx

There was a kernel bug causing top to show bogus values: http://lkml.org/lkml/2007/10/3/123 . However, it was purely a display thing.

----------

## gimpel

Oh yeah. Here we go. I have exactly the same problem with 2.6.24-rcX as no_hope.

I almost went nuts about this.

I'm running plain 2.6.24-rc2-git2 now.

no_hope,

This looks like the issue here: http://lkml.org/lkml/2007/10/31/169

I also use reiserfs.

----------

## i92guboj

A good way to check if the value reported by top is true or false is to look at the temperature.

If the cpu is 100% occupied for a long time, then your cpu temperature will be a lot higher. The difference is sensible enough.

----------

## gimpel

 *gimpel wrote:*   

> no_hope,
> 
> This looks like the issue here: http://lkml.org/lkml/2007/10/31/169
> 
> I also use reiserfs.

 

http://lkml.org/lkml/2007/11/6/33 seems related too, going to try the mm- and reiserfs writeback fix patch. 

That seems to fix that issue.

----------

## no_hope

 *i92guboj wrote:*   

> A good way to check if the value reported by top is true or false is to look at the temperature.
> 
> If the cpu is 100% occupied for a long time, then your cpu temperature will be a lot higher. The difference is sensible enough.

 

Will temperature rise even if the CPU is in wait state?

----------

## i92guboj

 *no_hope wrote:*   

>  *i92guboj wrote:*   A good way to check if the value reported by top is true or false is to look at the temperature.
> 
> If the cpu is 100% occupied for a long time, then your cpu temperature will be a lot higher. The difference is sensible enough. 
> 
> Will temperature rise even if the CPU is in wait state?

 

It will reaise if there is any real activity.

Note that in modern systems, the cpu always waste an important amount of time on wait states, even when really doing some hard work. This will continue to happen as long as the bus and memory speeds can't catch up the cpu clock speeds. So, wait states happen the same during normal operation. 

I am not an expert on the matter, and if someone could enlighten us it would be a good thing, but I think that If your cpu is going into wait status for a long time, then it is because there must be something running and doing some heavy i/o, even if ps and top do not report it for some reason.

I don't mean to start any polemic, and I can say if it is exactly the same issue. But this happened with reiserfs lots of times in the past, and this is why I don't even compile the reiserfs anymore in my kernel, nor do I use any reiserfs partition at all. Too many annoyances for a filesystem, if you ask me.

----------

