Re: 2.6.25-rc5-git6: Reported regressions from 2.6.24

[Gabriel C <crazy@frugalware.org>]

Gabriel C wrote:
> Thomas Gleixner wrote:
>> On Fri, 21 Mar 2008, Gabriel C wrote:
>>>>> Also, can you please reapply the reverted clocksource patch ? I have
>>>>> the feeling that the acpi_pm one was the real problem which was
>>>>> triggered the modfied watchdog.
>>>> Sure I can , will do so in some minutes and let you know.
>>> It took a bit longer sorry but I have more infos now.
>>>
>>> The acpi_pm was not related to that I still get the problem.
>>>
>>> Of course I still can try to find the commit which magically fixed acpi_pm if you really want.
>> Just if you are really bored. :) I would have asked if it had fixed
>> the TSC issue.
>>  
>>> It seems like it breaks only when you enable HT and only on 2 socket motherboards. 
>>> ( at least the ones I own , I know is old hardware but worked fine for me )
>> Hmm. I wonder why a dual socket board survives the initial sync test.
>>  
>>> Also disabling the second CPU and enabling HT works , enabling both
>>> CPUs and disabling HT works , booting with enabled HT and both CPUs
>>> but maxcpus=2 also works , booting with 2 CPUs and HT on breaks ,
>>> booting with both CPUs HT on but maxcpus=3 breaks also.
>>>
>>> Also I have another dual motherboard here 604 socket with 2 2,4 GHz
>>> Xeon's.  The motherboard has the storage controller somewhat broken
>>> but for a quick test it is still good :) and I see the same thing.
>>>
>>> Does that make any sense ?
>> Not really. Can you please revert the reverted revert again and run
>>
>> http://people.redhat.com/mingo/time-warp-test/time-warp-test.c
>>
>> on your machine with all CPUs and HT enabled ?
> 
> Sure , doing so now.
> 

Here the result on 2.6.25-rc6-00243-g028011e ( it was running 30++ minutes the time I was away for food =) )

...

 4 CPUs, running 4 parallel test-tasks.
checking for time-warps via:
- read time stamp counter (RDTSC) instruction (cycle resolution)
- gettimeofday (TOD) syscall (usec resolution)
- clock_gettime(CLOCK_MONOTONIC) syscall (nsec resolution)

| 1.46 us, TSC-warps:0 | 16.01 us, TOD-warps:0 | 16.10 us, CLOCK-warps:0

...

Gabriel