AMD64: timer is running twice as fast as it should (again??)

AMD64: timer is running twice as fast as it should (again??)

[Enrico Scholz]

Hello,

with 2.6 kernels, the timer on AMD64 runs exactly twice as fast as
expected. E.g. 'sleep 10' returns after 5 seconds external time.

This behavior was seen with Fedora Core 3 kernel 2.6.9-1.681_FC3 and
2.6.10-rc3-bk13 (both x86_64 mode).

System information can be found at
                http://www.tu-chemnitz.de/~ensc/hw/amd64



Enrico

Re: AMD64: timer is running twice as fast as it should (again??)

[Mark Nipper]

On 20 Dec 2004, Enrico Scholz wrote:
> with 2.6 kernels, the timer on AMD64 runs exactly twice as fast as
> expected. E.g. 'sleep 10' returns after 5 seconds external time.
> 
> This behavior was seen with Fedora Core 3 kernel 2.6.9-1.681_FC3 and
> 2.6.10-rc3-bk13 (both x86_64 mode).
> 
> System information can be found at
>                 http://www.tu-chemnitz.de/~ensc/hw/amd64

	Seem like something specific to Fedora or the bk branch
then because I'm running 2.6.10-rc3 under x86_64 and it sleeps as
long as it should.

-- 
Mark Nipper                                                e-contacts:
4475 Carter Creek Parkway                           nipsy@bitgnome.net
Apartment 724                               http://nipsy.bitgnome.net/
Bryan, Texas, 77802-4481           AIM/Yahoo: texasnipsy ICQ: 66971617
(979)575-3193                                      MSN: nipsy@tamu.edu

-----BEGIN GEEK CODE BLOCK-----
Version: 3.1
GG/IT d- s++:+ a- C++$ UBL++++$ P--->+++ L+++$ !E---
W++(--) N+ o K++ w(---) O++ M V(--) PS+++(+) PE(--)
Y+ PGP t+ 5 X R tv b+++@ DI+(++) D+ G e h r++ y+(**)
------END GEEK CODE BLOCK------

---begin random quote of the moment---
Whose woods these are I think I know.
His house is in the village though;
He will not see me stopping here
To watch his woods fill up with snow.

My little horse must think it queer
To stop without a farmhouse near
Between the woods and frozen lake
The darkest evening of the year.

He gives his harness bells a shake
To ask if there is some mistake.
The only other sound's the sweep
Of easy wind and downy flake.

The woods are lovely, dark and deep.
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.

 -- Robert Frost, _New Hampshire: A Poem with Notes and Grace
    Notes_, 1923
----end random quote of the moment----

Re: AMD64: timer is running twice as fast as it should (again??)

[Enrico Scholz]

Mark Nipper <nipsy@bitgnome.net> writes:

>> with 2.6 kernels, the timer on AMD64 runs exactly twice as fast as
>> expected. E.g. 'sleep 10' returns after 5 seconds external time.
>> 
>> This behavior was seen with Fedora Core 3 kernel 2.6.9-1.681_FC3 and
>> 2.6.10-rc3-bk13 (both x86_64 mode).
>> 
>> System information can be found at
>>                 http://www.tu-chemnitz.de/~ensc/hw/amd64
>
> 	Seem like something specific to Fedora or the bk branch
> then because I'm running 2.6.10-rc3 under x86_64 and it sleeps as
> long as it should.

Thanks for your testing but I can reproduce it both with vanilla 2.6.9
and 2.6.10-rc3. The used .config can be found at

          http://www.tu-chemnitz.de/~ensc/hw/amd64/config.txt




Enrico

Re: AMD64: timer is running twice as fast as it should (again??)

[Mark Nipper]

On 21 Dec 2004, Enrico Scholz wrote:
> > 	Seem like something specific to Fedora or the bk branch
> > then because I'm running 2.6.10-rc3 under x86_64 and it sleeps as
> > long as it should.
> 
> Thanks for your testing but I can reproduce it both with vanilla 2.6.9
> and 2.6.10-rc3. The used .config can be found at
> 
>           http://www.tu-chemnitz.de/~ensc/hw/amd64/config.txt

	Sounds like something specific to Fedora/glibc under
Fedora then.  I'm running Debian sid/gcc-3.4 and it works fine
under vanilla 2.6.10-rc3 (well, with reiser4 patches, but mostly
vanilla).

	I'd check to see if anyone else running Fedora x86_64 is
having similar troubles.

-- 
Mark Nipper                                                e-contacts:
4475 Carter Creek Parkway                           nipsy@bitgnome.net
Apartment 724                               http://nipsy.bitgnome.net/
Bryan, Texas, 77802-4481           AIM/Yahoo: texasnipsy ICQ: 66971617
(979)575-3193                                      MSN: nipsy@tamu.edu

-----BEGIN GEEK CODE BLOCK-----
Version: 3.1
GG/IT d- s++:+ a- C++$ UBL++++$ P--->+++ L+++$ !E---
W++(--) N+ o K++ w(---) O++ M V(--) PS+++(+) PE(--)
Y+ PGP t+ 5 X R tv b+++@ DI+(++) D+ G e h r++ y+(**)
------END GEEK CODE BLOCK------

---begin random quote of the moment---
If you're not part of the solution, you're part of the precipitate.
----end random quote of the moment----

Re: AMD64: timer is running twice as fast as it should (again??)

[Enrico Scholz]

Mark Nipper <nipsy@bitgnome.net> writes:

>> > 	Seem like something specific to Fedora or the bk branch
>> > then because I'm running 2.6.10-rc3 under x86_64 and it sleeps as
>> > long as it should.
>> 
>> Thanks for your testing but I can reproduce it both with vanilla 2.6.9
>> and 2.6.10-rc3. The used .config can be found at
>> 
>>           http://www.tu-chemnitz.de/~ensc/hw/amd64/config.txt
>
> 	Sounds like something specific to Fedora/glibc under
> Fedora then.

sorry, I do not see how a broken kernel-timer can be glibc related...  I
suspect something ACPI related; especially because there was a similar
discussion in July.



Enrico