Hello all,

i work in a web hosting compagny. We have a strange problem on many servers. 
The hardware clock of several server is totaly instable. This happen on many 
server, not all.
Symptoms:

root@computer:~# date && hwclock
Wed Jun  4 13:53:21 CEST 2008
Sat Jun  7 20:23:16 2008  -0.576925 seconds


root@computer:~# hwclock --systohc

root@computer:~# date && hwclock
Wed Jun  4 13:53:34 CEST 2008
Wed Jun  4 13:53:36 2008  -0.835749 seconds

(2 seconds !)

root@rd10:~# date && hwclock
Wed Jun  4 13:53:42 CEST 2008
Wed Jun  4 13:54:02 2008  -0.779573 seconds

(20 seconds !!)

I have try to pass clock or clocksource= hpet, pti to the kernel at boot: same 
troubles.


Kernel information:
cat /proc/version
Linux version 2.6.24.2 (root@XXXXXXX ) (gcc version 4.1.2 20061115 
(prerelease) (Debian 4.1.1-21)) #1 SMP Wed Feb 20 15:40:12 CET 2008

cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 8
model name      : Pentium III (Coppermine)
stepping        : 6
cpu MHz         : 797.548
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 mmx fxsr sse
bogomips        : 1596.12
clflush size    : 32

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 8
model name      : Pentium III (Coppermine)
stepping        : 6
cpu MHz         : 797.548
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 mmx fxsr sse
bogomips        : 1595.08
clflush size    : 32

cat /proc/ioports
0000-001f : dma1
0020-0021 : pic1
0040-0043 : timer0
0050-0053 : timer1
0060-006f : keyboard
0070-0077 : rtc
0080-008f : dma page reg
00a0-00a1 : pic2
00c0-00df : dma2
00f0-00ff : fpu
0170-0177 : 0000:00:0f.1
01f0-01f7 : 0000:00:0f.1
  01f0-01f7 : ide0
0220-0223 : ACPI PM1a_EVT_BLK
0230-0231 : ACPI PM1a_CNT_BLK
0240-0243 : ACPI PM_TMR
02f8-02ff : serial
0376-0376 : 0000:00:0f.1
03c0-03df : vga+
03f2-03f5 : floppy
03f6-03f6 : 0000:00:0f.1
  03f6-03f6 : ide0
03f7-03f7 : floppy DIR
03f8-03ff : serial
0408-040f : pnp 00:01
0cf8-0cff : PCI conf1
0f50-0f58 : pnp 00:01
1800-18ff : 0000:00:04.0
2000-20ff : 0000:00:01.0
  2000-20ff : cpqarray
2400-243f : 0000:00:02.0
  2400-243f : e100
2800-28ff : 0000:00:03.0
2c00-2c0f : 0000:00:0f.1


cat /proc/iomem
00000000-0009f7ff : System RAM
0009f800-0009ffff : reserved
000a0000-000bffff : Video RAM area
000c0000-000c7fff : Video ROM
000e8000-000edfff : Adapter ROM
000f0000-000fffff : System ROM
00100000-1fffbfff : System RAM
  00200000-005c7a77 : Kernel code
  005c7a78-00717f7b : Kernel data
  0075e000-007cfbc7 : Kernel bss
1fffc000-1fffffff : ACPI Tables
30000000-300fffff : 0000:00:02.0
30100000-3017ffff : 0000:00:01.0
30180000-3019ffff : 0000:00:03.0
c3000000-c3ffffff : 0000:00:03.0
c4dfef00-c4dfefff : 0000:00:04.0
c4dff000-c4dfffff : 0000:00:03.0
c4e00000-c4efffff : 0000:00:02.0
  c4e00000-c4efffff : e100
c4fff000-c4ffffff : 0000:00:02.0
  c4fff000-c4ffffff : e100
c5000000-c5ffffff : 0000:00:01.0
c6000000-c6ffffff : 0000:00:01.0
fec00000-fec0ffff : reserved
fee00000-fee0ffff : reserved
fff80000-ffffffff : reserved


lspci -vvvv
00:00.0 Host bridge: Broadcom CNB20LE Host Bridge (rev 06)
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort+ >SERR- <PERR-
        Latency: 64, Cache Line Size: 32 bytes

00:00.1 Host bridge: Broadcom CNB20LE Host Bridge (rev 06)
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 64, Cache Line Size: 32 bytes

00:01.0 RAID bus controller: LSI Logic / Symbios Logic 53C1510 (rev 02)
        Subsystem: Compaq Computer Corporation Integrated Array Controller
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 192 (7500ns min, 2000ns max), Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 16
        Region 0: I/O ports at 2000 [size=256]
        Region 1: Memory at c6000000 (32-bit, non-prefetchable) [size=16M]
        Region 2: Memory at c5000000 (32-bit, non-prefetchable) [size=16M]
        [virtual] Expansion ROM at 30100000 [disabled] [size=512K]
        Capabilities: [40] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA 
PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

00:02.0 Ethernet controller: Intel Corporation 82557/8/9 [Ethernet Pro 100] 
(rev 08)
        Subsystem: Compaq Computer Corporation NC3163 Fast Ethernet NIC 
(embedded, WOL)
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 64 (2000ns min, 14000ns max), Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 17
        Region 0: Memory at c4fff000 (32-bit, non-prefetchable) [size=4K]
        Region 1: I/O ports at 2400 [size=64]
        Region 2: Memory at c4e00000 (32-bit, non-prefetchable) [size=1M]
        [virtual] Expansion ROM at 30000000 [disabled] [size=1M]
        Capabilities: [dc] Power Management version 2
                Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA 
PME(D0+,D1+,D2+,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=2 PME-

00:03.0 VGA compatible controller: ATI Technologies Inc 3D Rage IIC 215IIC 
[Mach64 GT IIC] (rev 7a) (prog-if 00 [VGA])
        Subsystem: ATI Technologies Inc Rage IIC
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping+ SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 64 (2000ns min), Cache Line Size: 32 bytes
        Region 0: Memory at c3000000 (32-bit, prefetchable) [size=16M]
        Region 1: I/O ports at 2800 [size=256]
        Region 2: Memory at c4dff000 (32-bit, non-prefetchable) [size=4K]
        [virtual] Expansion ROM at 30180000 [disabled] [size=128K]
        Capabilities: [5c] Power Management version 1
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA 
PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

00:04.0 System peripheral: Compaq Computer Corporation Advanced System 
Management Controller
        Subsystem: Compaq Computer Corporation Unknown device b0f3
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Interrupt: pin A routed to IRQ 255
        Region 0: I/O ports at 1800 [size=256]
        Region 1: Memory at c4dfef00 (32-bit, non-prefetchable) [size=256]

00:0f.0 ISA bridge: Broadcom OSB4 South Bridge (rev 51)
        Subsystem: Broadcom OSB4 South Bridge
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 0

00:0f.1 IDE interface: Broadcom OSB4 IDE Controller (prog-if 8a [Master SecP 
PriP])
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- 
Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 64
        Region 0: [virtual] Memory at 000001f0 (32-bit, non-prefetchable) 
[disabled] [size=8]
        Region 1: [virtual] Memory at 000003f0 (type 3, non-prefetchable) 
[disabled] [size=1]
        Region 2: [virtual] Memory at 00000170 (32-bit, non-prefetchable) 
[disabled] [size=8]
        Region 3: [virtual] Memory at 00000370 (type 3, non-prefetchable) 
[disabled] [size=1]
        Region 4: I/O ports at 2c00 [size=16]