[mythtv-users] Video studder XvMC w/OSD

[Roger Heflin]

Krzysztof Adamski wrote:
> On Wed, 2008-02-04 at 20:00 -0500, Roger Heflin wrote:
>> Krzysztof Adamski wrote:
>>> On Wed, 2008-02-04 at 19:22 -0500, Roger Heflin wrote:
>>>> Mitch Gore wrote:
>>>>>> Yes, i also have the fade turned off.  With OSD Fade checked the stutter
>>>>>> is so bad its unwatchable.  It would be nice to get ride of it completely.
>>>>>> It really ruins the "experience" when you are watching/showing off Myth and
>>>>>> it skips a commercial and everyone is like wow thats cool.  Then it stutters
>>>>>> and looks like piece of junk.
>>>>>>
>>>>>> Mitchell
>>>>>>
>>>>> After some more investigation I noticed that the BOIS is reconizing the CPU
>>>>> as P4 3.0 ghz but its clock speed is set to 2Ghz.
>>>>>
>>>>> here is some output:
>>>>> [myth at mythfe ~]$ cat /proc/cpuinfo
>>>>> processor       : 0
>>>>> vendor_id       : GenuineIntel
>>>>> cpu family      : 15
>>>>> model           : 4
>>>>> model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
>>>>> stepping        : 1
>>>>> cpu MHz         : 1995.506
>>>>> cache size      : 1024 KB
>>>>> physical id     : 0
>>>>> siblings        : 2
>>>>> core id         : 0
>>>>> cpu cores       : 1
>>>>> fdiv_bug        : no
>>>>> hlt_bug         : no
>>>>> f00f_bug        : no
>>>>> coma_bug        : no
>>>>> fpu             : yes
>>>>> fpu_exception   : yes
>>>>> cpuid level     : 5
>>>>> wp              : yes
>>>>> flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov
>>>>> pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pebs
>>>>> bts sync_rdtsc pni monitor ds_cpl cid xtpr
>>>>> bogomips        : 4008.12
>>>>> clflush size    : 64
>>>>>
>>>>> processor       : 1
>>>>> vendor_id       : GenuineIntel
>>>>> cpu family      : 15
>>>>> model           : 4
>>>>> model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
>>>>> stepping        : 1
>>>>> cpu MHz         : 1995.506
>>>>> cache size      : 1024 KB
>>>>> physical id     : 0
>>>>> siblings        : 2
>>>>> core id         : 0
>>>>> cpu cores       : 1
>>>>> fdiv_bug        : no
>>>>> hlt_bug         : no
>>>>> f00f_bug        : no
>>>>> coma_bug        : no
>>>>> fpu             : yes
>>>>> fpu_exception   : yes
>>>>> cpuid level     : 5
>>>>> wp              : yes
>>>>> flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov
>>>>> pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pebs
>>>>> bts sync_rdtsc pni monitor ds_cpl cid xtpr
>>>>> bogomips        : 3974.91
>>>>> clflush size    : 64
>>>>>
>>>>>
>>>>> Maybe i need to update my BIOS.  Or is there some other thing i can change?
>>>>> I looked through BIOS settings but didnt see anything of intrest.
>>>>>
>>>>> Mitchell
>>>> Updating the bios may be required.
>>>>
>>>> I have seen motherboards that (for an unknown reason) detect the wrong cpu speed.
>>>>
>>>> You can try doing a "load failsafe", save and reboot and see what it does, and 
>>>> also a "load optimal" and save and reboot and check it, and also your bios may 
>>>> allow you to set a clock multiplier, if so you can calculate what the multiplier 
>>>> should be for 3.0 Ghz compared to what it currently is for 2.0Ghz, and set it to 
>>>> that.
>>> This has nothing to do with the BIOS, it is the powersaving system that
>>> lowers the CPU clock. Look for cpufreq daemon.
>>>
>>> K
>> If it were, cpufreq would be speeding things up, and that is a fairly old cpu, 
>> and it pre-dates Intel putting speedstep on their desktop cpus, they only did 
>> that very recently, and that cpu is not even a 64-bit capable cpu.
>>
>> And note that all of the p4 cpus that have speedstep have 2048mb of cache, he 
>> has only 1024mb, so and all with speedstep also have 64 bit, and cpuinfo shows 
>> that the processor is not capable of 64bit.
> 
> Sorry to contradict you, but I have a 32bit only P4 3G that only has
> 1024 of cache (I don't remember if it has HT since I always switch that
> off), so very likely he has an identical CPU to mine and it has ability
> to change the speed. It may not be speedstep, but the frequency can be
> lowered and the CPU runs slower.
> 
> K
>

K,

There is only 2 ways to slow down those cpus (I forgot about the other one), one 
is to change the bios clock multiplier, the other is to overheat them 
(thermal_throttle) and it is automatic, and not controllable by the kernel (it 
may be noted by some kernel/distributions).

Intel did not have any controllable powersaving features in those cpus, except 
for the automatic thermal_throttling.

Check /sys/devices/system/cpu/cpu0/thermal_throttle/count, if it is not 0 you 
have been thermal throttled at least once.