Losing too many ticks! .... on a VIA epia board

Losing too many ticks! .... on a VIA epia board

[Thomas S. Iversen]

Hi There

I have just hooked up my new via mainboard 
(http://www.viaembedded.com/product/epia_ms_spec.jsp?motherboardId=281)

and installed the latest linux kernel on the system (2.6.8). 
Unfortiunatly something is misbehaving with the timer/kernel interaction.

A snippet from dmesg:

agpgart: Detected VIA CLE266 chipset
agpgart: Maximum main memory to use for agp memory: 424M
agpgart: AGP aperture is 4M @ 0xe7000000
Losing some ticks... checking if CPU frequency changed.
e100: eth0: e100_watchdog: link up, 100Mbps, full-duplex
NET: Registered protocol family 17
Linux Kernel Card Services
  options:  [pci] [cardbus] [pm]
Losing some ticks... checking if CPU frequency changed.
NET: Registered protocol family 10
Disabled Privacy Extensions on device c0340d60(lo)
IPv6 over IPv4 tunneling driver
Losing some ticks... checking if CPU frequency changed.
eth0: no IPv6 routers present
apm: BIOS version 1.2 Flags 0x07 (Driver version 1.16ac)
apm: overridden by ACPI.
mtrr: 0xe0000000,0x1000000 overlaps existing 0xe0000000,0x800000
Losing some ticks... checking if CPU frequency changed.
padlock: Using VIA PadLock ACE for AES algorithm (multiblock).
Losing some ticks... checking if CPU frequency changed.
Losing some ticks... checking if CPU frequency changed.
Losing some ticks... checking if CPU frequency changed.
Losing some ticks... checking if CPU frequency changed.
.....
and then finally

Losing some ticks... checking if CPU frequency changed.
Losing some ticks... checking if CPU frequency changed.
Losing too many ticks!
TSC cannot be used as a timesource. 
Possible reasons for this are:
  You're running with Speedstep,
  You don't have DMA enabled for your hard disk (see hdparm),
  Incorrect TSC synchronization on an SMP system (see dmesg).
Falling back to a sane timesource now.


Furthermore editors like jed and emacs takes forever to start. A "strace 
emacs /somefile" shows that it hangs in a poll right after gettimeofday.

Any clues to what is wrong and how I go about fixing it?!

Regards Thomas, Denmark

Re: Losing too many ticks! .... on a VIA epia board

[Georg Schild]

> Losing some ticks... checking if CPU frequency changed.
> Losing some ticks... checking if CPU frequency changed.
> Losing too many ticks!
> TSC cannot be used as a timesource. Possible reasons for this are:
>  You're running with Speedstep,
>  You don't have DMA enabled for your hard disk (see hdparm),
>  Incorrect TSC synchronization on an SMP system (see dmesg).
> Falling back to a sane timesource now.
> 
> 
> Furthermore editors like jed and emacs takes forever to start. A "strace 
> emacs /somefile" shows that it hangs in a poll right after gettimeofday.
> 
> Any clues to what is wrong and how I go about fixing it?!
> 
> Regards Thomas, Denmark
> 

I don't have a clue but the same problem on an amd64 system. I am 
running a 64bit 2.6.9-rc1-mm4 kernel on my machine and if i add the boot 
parameter report_lost_ticks it reports the same messages as your 
machine. Since 2.6.7 there is this parameter, before the lost ticks 
where reported all the time. I always thought that this is a 64bit 
problem because i have heard from others which have this problem too. 
Why are we loosing ticks? On my system it happens almost when an acpi 
event occurs. I know that they aren't reported anymore but I don't like 
the thing that my processor (or timesource) looses something.

Georg Schild

Re: Losing too many ticks! .... on a VIA epia board

[Thomas S. Iversen]

On Tue, Sep 14, 2004 at 11:53:16AM +0200, Georg Schild wrote:

> I don't have a clue but the same problem on an amd64 system. I am

Do you have a VIA chipset on this system?

Regards Thomas

Re: Losing too many ticks! .... on a VIA epia board

[Georg Schild]

> Do you have a VIA chipset on this system?

Yes, it's a laptop with a k8t800 chipset. But I have some problems with 
the soulution to disable ACPI though it's a laptop and diabling ACPI 
would say no frequency scaling, no fan regulation etc. Does the PM_Timer 
work on amd64 or isn't it just for x86? I think that i had heard about 
that it wouldn't bring any effect on x86-64. We have discussed this 
issue for a long while on the gentoo amd64 forums though it looks like 
that just amd64 users have this problems.

Here a link but without any useful solution, we had the things with 
disabling ACPI or enabling the PM-Timer already.

http://forums.gentoo.org/viewtopic.php?t=191716

As I know this problem started with kernels later than 2.6.5, don't know 
the exact version, end ended with kernel 2.6.8 which only reports lost 
ticks > 100 by default. But we still loose ticks and i don't like this 
even if i don't see it anymore on dmesg.

Georg Schild

Re: Losing too many ticks! .... on a VIA epia board

[Thomas S. Iversen]

Thomas S. Iversen wrote:

> Any clues to what is wrong and how I go about fixing it?!

Well, I made a kernel without acpi support and the problem went away. 
Any clues to why that solved the problem?

Regards Thomas, Denmark

Re: Losing too many ticks! .... on a VIA epia board

[Prakash K. Cheemplavam]

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Thomas S. Iversen wrote:
| Thomas S. Iversen wrote:
|
|> Any clues to what is wrong and how I go about fixing it?!
|
|
| Well, I made a kernel without acpi support and the problem went away.
| Any clues to why that solved the problem?

Frequency scaling or anything alike? Have you tried using acpi pm timer?
This should prevent you from losing ticks.

Prakash
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Re: Losing too many ticks! .... on a VIA epia board

[Thomas S. Iversen]

Prakash K. Cheemplavam wrote:

> | Well, I made a kernel without acpi support and the problem went away.
> | Any clues to why that solved the problem?
>
> Frequency scaling or anything alike? Have you tried using acpi pm timer?
> This should prevent you from losing ticks.

Yeah, I found the acpi pm timer (a new option) and the problem went away.
I haven't got any frequency scaling included, so it's simply ACPI calls 
which
makes the system lose to many ticks :-(

Thomas