[Scip] Solving time

Stefan Heinz heinz at zib.de
Fri Mar 16 08:49:27 MET 2012


Hi Jacob,

yes the time displayed per default is the CPU time. That means for 
example if your job had all the time only 50% of a thread the clock goes 
half as fast as the wall clock time. In case you "see" that your job 
gets 100% of a thread all the time, then the wall clock time should be 
almost equal to the CPU time. Please not that the system time is not 
included in the CPU time.

On 03/15/2012 06:24 PM, Jacob Spönemann wrote:
>  Hi Stefan,
>
> thanks for the fast reply.
>
> I'm using a dual-core system and four parallel threads are provided. 
> SCIP uses only one thread. Could it possible, that this causes the 
> deviating time values? So SCIP displays that amount of time that is 
> used in terms of a "fully utilized CPU"? For example, SCIP is running 
> for 320 minutes and displays 80 minutes.
That could be the case if SCIP only got (80/320 * 100)% of one thread 
all the time.

Best Stefan
>
> Best regards,
>
> Jacob
>
> Am 15.03.2012 17:21, schrieb Stefan Heinz:
>> Hi Jacob,
>>
>> You can chanege the clock type via
>>
>> SCIP> set timing clocktype
>>
>>
>>
>> On 03/15/12 16:44, Jacob Spönemann wrote:
>>>    Hi,
>>>
>>> the output of the solving process contains the field "time" (first
>>> column of the output). Which time is displayed there?
>> If you did not change the clock type, it is the CPU time.
>>
>>
>>> Unfortunately, I could not find any detailed explanation in the SCIP
>>> documentation regarding elements of the output.
>> You can just ask the shell:
>>
>>  SCIP> display displaycols
>>
>>>
>>> My current MIP job now is running for 24 hours and "time" tells me 
>>> "420m".
>> That is strange. This indicates that your job did not got 100% of the 
>> CPU or you had a lot of system calls. If it is the latter case we 
>> would like get the instance if possible, such that we can check where 
>> these system calls come form. In any case you might want to change 
>> from CPU time to wall clock time.
>>
>> SCIP> set timing clocktype 2
>>
>> Best Stefan
>>> Best regards,
>>>
>>> Jacob
>>> _______________________________________________
>>> Scip mailing list
>>> Scip at zib.de
>>> http://listserv.zib.de/mailman/listinfo/scip
>>
>



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