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CPU% Allocation to Batch jobs

 
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rajeshsundarraj

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Joined: 24 Sep 2010
Posts: 2
Location: chennai

PostPosted: Wed Feb 09, 2011 9:36 am    Post subject: CPU% Allocation to Batch jobs
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CPU% Allocation to Batch jobs

In Batch run, there is a difference in CPU% allocation to different batch jobs, eventhough the CLASS is same for the jobs.

Below are the three instances which I have taken from SDSF ; DA

Instance 1:
Code:
NP   JOBNAME   CPU% ASID ASIDX  EXCP-Cnt   CPU-Time SR Status SysName  SPag SC
     JOBAS72D  0.87   67  0043    432426     101.50           SYSA      100   
     JOBAS74D  0.17   96  0060     12918       1.11           SYSA      100   
     JOBAT48D  1.11   94  005E     63400       4.76           SYSA      100   
     JOBAT74D  0.17  117  0075     12403       1.07           SYSA      100   
     JOBAU48D  1.14  289  0121     77317       5.83           SYSA      100   
     JOBA0G2D 10.56  100  0064     94867      94.48           SYSA      100   
     JOBA098B  2.71   92  005C     62194      16.95           SYSA      100   

Instance 2:
Code:
NP   JOBNAME   CPU% ASID ASIDX  EXCP-Cnt   CPU-Time SR Status SysName  SPag SCP
      JOBAS72D  0.84   67  0043    434708     102.04           SYSA       90   
      JOBAS74D  0.18   96  0060     14294       1.22           SYSA       90   
      JOBAV74D  0.17  280  0118     13523       1.17           SYSA       90   
      JOBAW74D  0.19  288  0120     13265       1.23           SYSA       90   
      JOBA0G2D 10.83  100  0064    101412     101.49           SYSA       90   
      JOBA042D  1.38   93  005D     28731      13.01           SYSA       90   
      JOBA049D  2.93   88  0058      1496       1.89           SYSA       90   

Instance 3:

Code:
NP   JOBNAME   CPU% ASID ASIDX  EXCP-Cnt   CPU-Time SR Status SysName  SPag S
      JOBAS72D  0.76   67  0043    436089     102.36           SYSA       93 
      JOBAS74D  0.16   96  0060     15107       1.29           SYSA       93 
      JOBAT48D  1.08   94  005E     79321       5.93           SYSA       93 
      JOBAT74D  0.16  117  0075     14506       1.25           SYSA       93 
      JOBA0G2D 11.94  100  0064    106232     106.59           SYSA       93 
      JOBA049D  8.58   88  0058      3956       5.56           SYSA       93 
      JOBA092D  5.97   99  0063    287855      91.20           SYSA       93 

In the above case, Two concerned jobs are JOBAS72D(first job in the list) and JOBA0G2D(high CPU%).
Mainframe team told that it will be decided by CPU internally.

JOBAS72D : it copies one VSAm to another VSAm using IDCAMS repro
JOBA0G2D : Applicaion Program.

Is there any possibility to control CPU% allocation apart from class parameter.

Just waiting for your views. If you need any more information, please let me know.
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed Feb 09, 2011 9:50 am    Post subject:
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Hello and welcome to the forum,

Quote:
there is a difference in CPU% allocation to different batch jobs

Some batch jobs require more cpu time than others. Some jobs use less cpu% because they are "waiting" on something (i/o to some file, a database interaction, etc).

From what you have posted, i see nothing that indicates a problem. The 2 jobs you mention are the 2 jobs that are doing the most work at the time the "snapshots" were taken.

Why does someone believe there is reason for concern?

When posting things that need to be aligned (code, jcl, file data, screen data) use the Code tag. Then Preview to see your post the way it will appear to the forum. When it looks as you want, Submit.
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rajeshsundarraj

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Joined: 24 Sep 2010
Posts: 2
Location: chennai

PostPosted: Wed Feb 09, 2011 10:45 am    Post subject:
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Thanks for the Greeting Mr. Scherrer.

Yes, Some jobs requires more CPU time than others.
This is not the problem, but analysing various factors affecting Elapsed time apart from CPU time, EXCP, Mainframe Load, database access and storage factors.

I saw this CPU% factor and misunderstood that it is Allocation factor.

Quote:
Some jobs use less cpu%


Above statement made me to think that it is not the allocation factor but it is used one.


Thanks for your reply and your suggestion on alignment. I will take care. icon_smile.gif
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed Feb 09, 2011 11:07 am    Post subject:
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Hello,

I'm not familiar with the term "allocation factor". This is not an industry-wide term?

Keep in mind the cpu% is the percent of the cpu currently being used by the process. The CPU Time is an accumulation of cpu used. They are not directly related.
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Robert Sample

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Joined: 06 Jun 2008
Posts: 8117
Location: East Dubuque, Illinois, USA

PostPosted: Wed Feb 09, 2011 4:18 pm    Post subject:
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Workload Manager (WLM) is the basic control mechanism for the system -- including CPU -- and it is possible to select individual jobs to run in certain service classes in WLM. So yes, there are ways, other than job class, to control use of the CPU. Workload management can be a very complex topic and there are manuals (and Redbooks) available to help optimize system resource usage.

However, there is nothing unusual or different about jobs in the same job class using different amount of CPU -- some jobs need more CPU time than other jobs. If you are really that concerned, talk to your site support group about the WLM policies in use at your site.
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