system clock speed too high?

Andreas Haumer (andreas@xss.co.at)
Mon, 02 Jun 2003 21:40:43 +0200


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Hi!

(I've already reported this previously as post scriptum
to a different bugreport, so it might have slipped through
unnoticed...)

I have a quite strange phenomenon here: I see a ~2.5 times
speed up of system time on a Asus AP1700-S5 server with
Linux-2.4.21-rc6-ac1.
Simple proof: a "sleep 300" command terminates after exactly
120 seconds of wall clock time.

Or just look at this:
root@setup:~ {544} $ ntpdate ntp.xss.co.at; ntpdate ntp.xss.co.at; sleep 300; ntpdate ntp.xss.co.at
2 Jun 21:24:45 ntpdate[3768]: step time server 194.152.162.17 offset -38.679740 sec
2 Jun 21:24:45 ntpdate[3769]: adjust time server 194.152.162.17 offset -0.069998 sec
2 Jun 21:26:45 ntpdate[3786]: step time server 194.152.162.17 offset -180.053781 sec

Impressive, isn't it?

This "acceleration" of time shows with other time measures,
like "date", system uptime, process time, etc., too.

(HZ is still defined as 100, I haven't changed anything in
the kernel sources)

System info:

Asus AP1700-S5, Asus PR-DLS533 Motherboard, Intel Xeon 2.4GHz CPU, 512MB RAM

root@setup:~ {545} $ uname -a
Linux setup 2.4.21-rc6-ac1 #1 SMP Sat May 31 20:04:18 CEST 2003 i686 unknown

root@setup:~ {546} $ lspci -v
00:00.0 Host bridge: ServerWorks CNB20-HE Host Bridge (rev 31)
Flags: fast devsel

00:00.1 Host bridge: ServerWorks CNB20-HE Host Bridge
Flags: fast devsel

00:00.2 Host bridge: ServerWorks CNB20-HE Host Bridge
Flags: fast devsel

00:02.0 Ethernet controller: Intel Corp. 82540EM Gigabit Ethernet Controller (rev 02)
Subsystem: Intel Corp. 82540EM Gigabit Ethernet Controller
Flags: bus master, 66Mhz, medium devsel, latency 32, IRQ 18
Memory at fd800000 (32-bit, non-prefetchable) [size=128K]
I/O ports at d800 [size=64]
Capabilities: [dc] Power Management version 2
Capabilities: [e4] PCI-X non-bridge device.
Capabilities: [f0] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-

00:03.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27) (prog-if 00 [VGA])
Subsystem: ATI Technologies Inc: Unknown device 8008
Flags: bus master, stepping, medium devsel, latency 32, IRQ 46
Memory at fc000000 (32-bit, non-prefetchable) [size=16M]
I/O ports at d400 [size=256]
Memory at fb800000 (32-bit, non-prefetchable) [size=4K]
Expansion ROM at febe0000 [disabled] [size=128K]
Capabilities: [5c] Power Management version 2

00:0f.0 ISA bridge: ServerWorks CSB5 South Bridge (rev 93)
Subsystem: ServerWorks CSB5 South Bridge
Flags: bus master, medium devsel, latency 32

00:0f.1 IDE interface: ServerWorks CSB5 IDE Controller (rev 93) (prog-if 8a [Master SecP PriP])
Subsystem: ServerWorks CSB5 IDE Controller
Flags: bus master, medium devsel, latency 64
I/O ports at <ignored>
I/O ports at <ignored>
I/O ports at <ignored>
I/O ports at <ignored>
I/O ports at a800 [size=16]

00:0f.2 USB Controller: ServerWorks OSB4/CSB5 OHCI USB Controller (rev 05) (prog-if 10 [OHCI])
Subsystem: ServerWorks OSB4/CSB5 OHCI USB Controller
Flags: bus master, medium devsel, latency 32, IRQ 11
Memory at fb000000 (32-bit, non-prefetchable) [size=4K]

00:0f.3 Host bridge: ServerWorks GCLE Host Bridge
Subsystem: ServerWorks: Unknown device 0230
Flags: bus master, medium devsel, latency 0

00:10.0 Host bridge: ServerWorks: Unknown device 0101 (rev 03)
Flags: 66Mhz, medium devsel
Capabilities: [60]
00:10.2 Host bridge: ServerWorks: Unknown device 0101 (rev 03)
Flags: 66Mhz, medium devsel
Capabilities: [60]
00:11.0 Host bridge: ServerWorks: Unknown device 0101 (rev 03)
Flags: 66Mhz, medium devsel
Capabilities: [60]
00:11.2 Host bridge: ServerWorks: Unknown device 0101 (rev 03)
Flags: 66Mhz, medium devsel
Capabilities: [60]
02:04.0 SCSI storage controller: LSI Logic / Symbios Logic 53c1030 (rev 07)
Subsystem: LSI Logic / Symbios Logic: Unknown device 1000
Flags: bus master, 66Mhz, medium devsel, latency 72, IRQ 22
I/O ports at a000 [size=256]
Memory at fa000000 (64-bit, non-prefetchable) [size=64K]
Memory at f9800000 (64-bit, non-prefetchable) [size=64K]
Expansion ROM at fe900000 [disabled] [size=1M]
Capabilities: [50] Power Management version 2
Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-
Capabilities: [68]
02:04.1 SCSI storage controller: LSI Logic / Symbios Logic 53c1030 (rev 07)
Subsystem: LSI Logic / Symbios Logic: Unknown device 1000
Flags: bus master, 66Mhz, medium devsel, latency 72, IRQ 23
I/O ports at 9800 [size=256]
Memory at f9000000 (64-bit, non-prefetchable) [size=64K]
Memory at f8800000 (64-bit, non-prefetchable) [size=64K]
Expansion ROM at fe800000 [disabled] [size=1M]
Capabilities: [50] Power Management version 2
Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-
Capabilities: [68]
03:02.0 Ethernet controller: Intel Corp. 82544GC Gigabit Ethernet Controller (LOM) (rev 02)
Subsystem: Intel Corp.: Unknown device 110d
Flags: bus master, 66Mhz, medium devsel, latency 32, IRQ 19
Memory at f8000000 (64-bit, non-prefetchable) [size=128K]
Memory at f7800000 (64-bit, non-prefetchable) [size=128K]
I/O ports at 9400 [size=32]
Expansion ROM at fe7e0000 [disabled] [size=128K]
Capabilities: [dc] Power Management version 2
Capabilities: [e4] PCI-X non-bridge device.
Capabilities: [f0] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-

root@setup:~ {547} $ cat /proc/interrupts
CPU0 CPU1
0: 1737732 1760169 IO-APIC-edge timer
1: 260 260 IO-APIC-edge keyboard
2: 0 0 XT-PIC cascade
4: 10 10 IO-APIC-edge serial
15: 5 17 IO-APIC-edge ide1
18: 22903530 23147515 IO-APIC-level eth0
22: 1695902 1726918 IO-APIC-level ioc0
23: 25 17 IO-APIC-level ioc1
NMI: 0 0
LOC: 1398848 1398847
ERR: 0
MIS: 0

Any ideas?

- - andreas

- --
Andreas Haumer | mailto:andreas@xss.co.at
*x Software + Systeme | http://www.xss.co.at/
Karmarschgasse 51/2/20 | Tel: +43-1-6060114-0
A-1100 Vienna, Austria | Fax: +43-1-6060114-71
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