2.6.27.7 built for Geode: Clock drift

2.6.27.7 built for Geode: Clock drift

[Harald Dunkel]

[-- Attachment #1: Type: text/plain, Size: 1087 bytes --]

Hi folks,

If I build a kernel for AMD Geode, then I see a clock drift of appr.
30 min. to 1 hour per day. If I build the same kernel for i486, then
the clock drift is gone. Running ntp makes no difference.

Hardware is a Linutop PC. /proc/cpuinfo says

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 5
model           : 10
model name      : Geode(TM) Integrated Processor by AMD PCS
stepping        : 2
cpu MHz         : 0.000
cache size      : 128 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu de pse tsc msr cx8 sep pge cmov clflush mmx mmxext 3dnowext 3dnow
bogomips        : 429.05
clflush size    : 32
power management:

BTW, the CPU is running with 500 MHz (AFAIK). 0.000 MHz is surely not
correct. /proc/cpuinfo reports the same for both kernels.

Attached is the diff of the config files. Please mail if you are
interested in the complete config files, or if I can help to track
this down.


Regards

Harri

[-- Attachment #2: config.diff --]
[-- Type: text/x-diff, Size: 1904 bytes --]

--- config-2.6.27.7-486	2008-12-02 03:36:11.000000000 +0100
+++ config-2.6.27.7-geode	2008-11-23 10:46:54.000000000 +0100
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
 # Linux kernel version: 2.6.27.7
-# Mon Dec  1 22:42:26 2008
+# Sun Nov 23 05:01:04 2008
 #
 # CONFIG_64BIT is not set
 CONFIG_X86_32=y
@@ -56,7 +56,7 @@
 CONFIG_EXPERIMENTAL=y
 CONFIG_BROKEN_ON_SMP=y
 CONFIG_INIT_ENV_ARG_LIMIT=32
-CONFIG_LOCALVERSION="-486"
+CONFIG_LOCALVERSION="-geode"
 # CONFIG_LOCALVERSION_AUTO is not set
 CONFIG_SWAP=y
 CONFIG_SYSVIPC=y
@@ -197,7 +197,7 @@
 # CONFIG_PARAVIRT_DEBUG is not set
 # CONFIG_MEMTEST is not set
 # CONFIG_M386 is not set
-CONFIG_M486=y
+# CONFIG_M486 is not set
 # CONFIG_M586 is not set
 # CONFIG_M586TSC is not set
 # CONFIG_M586MMX is not set
@@ -215,7 +215,7 @@
 # CONFIG_MWINCHIP2 is not set
 # CONFIG_MWINCHIP3D is not set
 # CONFIG_MGEODEGX1 is not set
-# CONFIG_MGEODE_LX is not set
+CONFIG_MGEODE_LX=y
 # CONFIG_MCYRIXIII is not set
 # CONFIG_MVIAC3_2 is not set
 # CONFIG_MVIAC7 is not set
@@ -227,15 +227,16 @@
 CONFIG_X86_CMPXCHG=y
 CONFIG_X86_L1_CACHE_SHIFT=7
 CONFIG_X86_XADD=y
-# CONFIG_X86_PPRO_FENCE is not set
-CONFIG_X86_F00F_BUG=y
 CONFIG_X86_WP_WORKS_OK=y
 CONFIG_X86_INVLPG=y
 CONFIG_X86_BSWAP=y
 CONFIG_X86_POPAD_OK=y
-CONFIG_X86_ALIGNMENT_16=y
 CONFIG_X86_INTEL_USERCOPY=y
+CONFIG_X86_USE_PPRO_CHECKSUM=y
+CONFIG_X86_USE_3DNOW=y
+CONFIG_X86_TSC=y
 CONFIG_X86_MINIMUM_CPU_FAMILY=4
+CONFIG_X86_DEBUGCTLMSR=y
 CONFIG_HPET_TIMER=y
 CONFIG_HPET_EMULATE_RTC=y
 CONFIG_DMI=y
@@ -423,6 +424,7 @@
 # CONFIG_MCA_PROC_FS is not set
 CONFIG_SCx200=m
 CONFIG_SCx200HR_TIMER=m
+CONFIG_GEODE_MFGPT_TIMER=y
 # CONFIG_OLPC is not set
 CONFIG_K8_NB=y
 # CONFIG_PCCARD is not set
@@ -1919,6 +1921,7 @@
 CONFIG_ADVANTECH_WDT=m
 CONFIG_ALIM1535_WDT=m
 CONFIG_ALIM7101_WDT=m
+CONFIG_GEODE_WDT=m
 CONFIG_SC520_WDT=m
 CONFIG_EUROTECH_WDT=m
 CONFIG_IB700_WDT=m

Re: 2.6.27.7 built for Geode: Clock drift

[Jordan Crouse]

Harald Dunkel wrote:
> Hi folks,
> 
> If I build a kernel for AMD Geode, then I see a clock drift of appr.
> 30 min. to 1 hour per day. If I build the same kernel for i486, then
> the clock drift is gone. Running ntp makes no difference.
> 
> Hardware is a Linutop PC. /proc/cpuinfo says
> 
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 5
> model           : 10
> model name      : Geode(TM) Integrated Processor by AMD PCS
> stepping        : 2
> cpu MHz         : 0.000
> cache size      : 128 KB
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : no
> coma_bug        : no
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> wp              : yes
> flags           : fpu de pse tsc msr cx8 sep pge cmov clflush mmx mmxext 3dnowext 3dnow
> bogomips        : 429.05
> clflush size    : 32
> power management:
> 
> BTW, the CPU is running with 500 MHz (AFAIK). 0.000 MHz is surely not
> correct. /proc/cpuinfo reports the same for both kernels.

Hmm - we've heard reports of this before, but nothing came of it.  I 
would be interested in a chance to debug it this time.

Please try turning off CONFIG_GEODE_MFGPT_TIMER=y and try again.  Also, 
try something in the 2.6.28 family to rule out fixes in the timer subsystem.

Thanks,
Jordan

Re: 2.6.27.7 built for Geode: Clock drift

[john stultz]

On Tue, Dec 2, 2008 at 10:36 AM, Harald Dunkel
<harald.dunkel@t-online.de> wrote:
> Hi folks,
>
> If I build a kernel for AMD Geode, then I see a clock drift of appr.
> 30 min. to 1 hour per day. If I build the same kernel for i486, then
> the clock drift is gone. Running ntp makes no difference.

For both configs, can you run:
   cat /sys/devices/system/clocksource/clocksource0/available_clocksource
and:
   cat /sys/devices/system/clocksource/clocksource0/current_clocksource

Then send back the output?

thanks
-john

Re: 2.6.27.7 built for Geode: Clock drift

[Harald Dunkel]

john stultz wrote:
> 
> For both configs, can you run:
>    cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> and:
>    cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> 
> Then send back the output?
> 

Sure. For 486:

% cat /sys/devices/system/clocksource/clocksource0/available_clocksource
pit jiffies
% cat /sys/devices/system/clocksource/clocksource0/current_clocksource
pit


For Geode (clock is running too fast):
% cat /sys/devices/system/clocksource/clocksource0/available_clocksource
jiffies
% cat /sys/devices/system/clocksource/clocksource0/current_clocksource
jiffies


dmesg says for Geode:

:
TSC: Unable to calibrate against PIT
TSC: No reference (HPET/PMTIMER) available
Marking TSC unstable due to could not calculate TSC khz
:


Regards

Harri

Re: 2.6.27.7 built for Geode: Clock drift

[Harald Dunkel]

Hi Jordan,

Jordan Crouse wrote:
> 
> Hmm - we've heard reports of this before, but nothing came of it.  I 
> would be interested in a chance to debug it this time.
> 
> Please try turning off CONFIG_GEODE_MFGPT_TIMER=y and try again.  Also, 
> try something in the 2.6.28 family to rule out fixes in the timer 
> subsystem.
> 
> Thanks,
> Jordan
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-- 
Dipl.-Ing. Harald Dunkel     | "They that can give up liberty to obtain
Muehlenbachstr. 3            | a little temporary safety deserve neither
52134 Herzogenrath, Germany  | liberty nor safety."
+49 2407 565 105             |            Benjamin Franklin, 1706 - 1790

Re: 2.6.27.7 built for Geode: Clock drift

[Harald Dunkel]

Hi Jordan,

Sorry for the empty reply. I clicked on [Send] by accident.

Jordan Crouse wrote:
> 
> Hmm - we've heard reports of this before, but nothing came of it.  I 
> would be interested in a chance to debug it this time.
> 
> Please try turning off CONFIG_GEODE_MFGPT_TIMER=y and try again.

AFAICS this was already set.

> Also, 
> try something in the 2.6.28 family to rule out fixes in the timer 
> subsystem.
> 

The build is running, but it is a slow machine.


Regards

Harri

Re: 2.6.27.7 built for Geode: Clock drift

[Jordan Crouse]

Harald Dunkel wrote:
> Hi Jordan,
> 
> Sorry for the empty reply. I clicked on [Send] by accident.
> 
> Jordan Crouse wrote:
>>
>> Hmm - we've heard reports of this before, but nothing came of it.  I 
>> would be interested in a chance to debug it this time.
>>
>> Please try turning off CONFIG_GEODE_MFGPT_TIMER=y and try again.
> 
> AFAICS this was already set.

You mean set prior to 2.6.27?  I know, but if there is a regression, 
that would help narrow it down.

Jordan

Re: 2.6.27.7 built for Geode: Clock drift

[Harald Dunkel]

Jordan Crouse wrote:
> Also, 
> try something in the 2.6.28 family to rule out fixes in the timer 
> subsystem.
> 

Using 2.6.28-rc7 the problem seems to be gone. There was no complain
about TSC in dmesg, and clock speed is OK. (ntp is off.)


Many thanx

Harri

Re: 2.6.27.7 built for Geode: Clock drift

[john stultz]

On Sat, 2008-12-06 at 07:09 +0100, Harald Dunkel wrote:
> john stultz wrote:
> > 
> > For both configs, can you run:
> >    cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> > and:
> >    cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> > 
> > Then send back the output?
> > 
> 
> Sure. For 486:
> 
> % cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> pit jiffies
> % cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> pit
> 
> 
> For Geode (clock is running too fast):
> % cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> jiffies
> % cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> jiffies
> 
> 
> dmesg says for Geode:
> 
> :
> TSC: Unable to calibrate against PIT
> TSC: No reference (HPET/PMTIMER) available
> Marking TSC unstable due to could not calculate TSC khz

Could you send your .config?

It seems the PIT (which is used in 486 build) is being disabled in the
Geode config. However, I thought the Geode's had their own clocksources,
either the SCx200 or the GEODE_MFGPT_TIMER. Maybe one of those needs to
be enabled?

thanks
-john

Re: 2.6.27.7 built for Geode: Clock drift

[Jordan Crouse]

john stultz wrote:
> On Sat, 2008-12-06 at 07:09 +0100, Harald Dunkel wrote:
>> john stultz wrote:
>>> For both configs, can you run:
>>>    cat /sys/devices/system/clocksource/clocksource0/available_clocksource
>>> and:
>>>    cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>>>
>>> Then send back the output?
>>>
>> Sure. For 486:
>>
>> % cat /sys/devices/system/clocksource/clocksource0/available_clocksource
>> pit jiffies
>> % cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>> pit
>>
>>
>> For Geode (clock is running too fast):
>> % cat /sys/devices/system/clocksource/clocksource0/available_clocksource
>> jiffies
>> % cat /sys/devices/system/clocksource/clocksource0/current_clocksource
>> jiffies
>>
>>
>> dmesg says for Geode:
>>
>> :
>> TSC: Unable to calibrate against PIT
>> TSC: No reference (HPET/PMTIMER) available
>> Marking TSC unstable due to could not calculate TSC khz
> 
> Could you send your .config?
> 
> It seems the PIT (which is used in 486 build) is being disabled in the
> Geode config. However, I thought the Geode's had their own clocksources,
> either the SCx200 or the GEODE_MFGPT_TIMER. Maybe one of those needs to
> be enabled?

He sent his original config in his first email - GEODE_MFGPT_TIMER was 
enabled. Its not always certain that there are MFGPT timers available 
(prior to about the middle of this year, most Geode BIOSes took all the 
timers for themselves).  But in any case the system should fall back to 
PIT automatically, so regardless of more advanced timers. the absence of 
a PIT is troubling.

Jordan