IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

CPU TIME to REAL TIME (Clock Time)


IBM Mainframe Forums -> JCL & VSAM
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 1:58 pm
Reply with quote

Hi,

I wanted to know how can we convert "TOT CPU TIME" in a JCL execution log to Real time.

Example - JCL log shows

Code:

TOT CPU TIME=  1.89 TOT ELAPSED TIME= 19.12


So How much TOT CPU TIME 1.89 = ? (Actual clock time)
Back to top
View user's profile Send private message
enrico-sorichetti

Superior Member


Joined: 14 Mar 2007
Posts: 10833
Location: italy

PostPosted: Tue Jan 17, 2012 2:22 pm
Reply with quote

the CPU time is the time that the CPU was busy executing Your <program> instructions
it is completely unrelated to the REAL (clock) time

ELAPSED TIME = CPU TIME + WAIT TIME (*)

nothing more, nothing less

(*) true only for strictly single thread/task processes
zOS will anyway under the covers carry on some multitasking
so sometimes the elapsed might be less than the <sum>
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 2:49 pm
Reply with quote

Thanks Enrico...

I want to know... That in this case Example CPU TIME = 1.89, which means 1 Minute and 89 seconds. (This is on scale of 100)

But actually seconds should be <= 59.

So how can we convert 1.89 to clock time.
Back to top
View user's profile Send private message
Bill Woodger

Moderator Emeritus


Joined: 09 Mar 2011
Posts: 7309
Location: Inside the Matrix

PostPosted: Tue Jan 17, 2012 3:09 pm
Reply with quote

1.89 * 60 = number of seconds

divide number of seconds by 60, which gives minutes, and the remainder is the number of seconds that have not reached to the next minute.

Another way to look at it is 0.89 * 60. Result from any of these will always be < 60.

I may be misunderstanding something about what you are asking.
Back to top
View user's profile Send private message
Garry Carroll

Senior Member


Joined: 08 May 2006
Posts: 1175
Location: Dublin, Ireland

PostPosted: Tue Jan 17, 2012 3:13 pm
Reply with quote

gylbharat wrote:
Thanks Enrico...

I want to know... That in this case Example CPU TIME = 1.89, which means 1 Minute and 89 seconds. (This is on scale of 100)

But actually seconds should be <= 59.

So how can we convert 1.89 to clock time.


It doesn't mean 89sec, it means 0.89 of a minute or (60s * 0.89) = 53.4 sec

Garry.
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 3:17 pm
Reply with quote

Garry Carroll wrote:
gylbharat wrote:
Thanks Enrico...

I want to know... That in this case Example CPU TIME = 1.89, which means 1 Minute and 89 seconds. (This is on scale of 100)

But actually seconds should be <= 59.

So how can we convert 1.89 to clock time.


It doesn't mean 89sec, it means 0.89 of a minute or (60s * 0.89) = 53.4 sec

Garry.


So total CPU TIME is 1 Minute and 53.4 Sec ?

As this 1 is also on scale of 100. Dont we have to convert it to Sec?
Back to top
View user's profile Send private message
Bill Woodger

Moderator Emeritus


Joined: 09 Mar 2011
Posts: 7309
Location: Inside the Matrix

PostPosted: Tue Jan 17, 2012 3:26 pm
Reply with quote

A minute is 60 seconds. 1/100th of a minute is 0.6 seconds.

If you want the CPU time in seconds, you have to convert it.
Back to top
View user's profile Send private message
Garry Carroll

Senior Member


Joined: 08 May 2006
Posts: 1175
Location: Dublin, Ireland

PostPosted: Tue Jan 17, 2012 3:28 pm
Reply with quote

As Bill suggests - I may be misunderstanding something about what you are asking.

Where are you getting the CPU time figure? and the reference that it's on a scale of 100?

Garry.
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 3:30 pm
Reply with quote

I am getting from the JCL output.
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 3:34 pm
Reply with quote

Can you show me how to convert 1.89 to seconds?
Back to top
View user's profile Send private message
Garry Carroll

Senior Member


Joined: 08 May 2006
Posts: 1175
Location: Dublin, Ireland

PostPosted: Tue Jan 17, 2012 3:38 pm
Reply with quote

gylbharat wrote:
Can you show me how to convert 1.89 to seconds?


seconds = (1.89 * 60) = 113.4s

Garry.
Back to top
View user's profile Send private message
gylbharat

Active Member


Joined: 31 Jul 2009
Posts: 565
Location: Bangalore

PostPosted: Tue Jan 17, 2012 3:46 pm
Reply with quote

Thanks Garry... Was getting confused icon_smile.gif
Back to top
View user's profile Send private message
Anuj Dhawan

Superior Member


Joined: 22 Apr 2006
Posts: 6250
Location: Mumbai, India

PostPosted: Tue Jan 17, 2012 3:49 pm
Reply with quote

Half-a-minute or 0.5 minutes (note, I did not say 0.30 minutes) or 30 seconds (0.5 x 60 seconds = 30.0 seconds) -- just differnt way of saying the same thing. As they say, a rose by any other name... .
Back to top
View user's profile Send private message
Robert Sample

Global Moderator


Joined: 06 Jun 2008
Posts: 8651
Location: Dubuque, Iowa, USA

PostPosted: Tue Jan 17, 2012 9:09 pm
Reply with quote

Elapsed time is the actual amount of wall clock time the job (or step) took. This number depends upon (among other factors):
- speed of the machine
- how many address spaces (tasks) are running at the same time
- the relative priority of your job against other tasks
- how busy the CPU is
- how much channel contention there is for the channels your task uses
- how much volume contention there is for the disk volumes your task uses
- time spent performing I/O (which includes making the request, actual reading or writing the data, and waiting for the data to come back / go to the device)
- the WLM (Workload Manager) policy in use at your site

True example: at our site, a compile job is considered discretionary (that is, it runs when nothing else wants the CPU). When the machine is not busy, a typical compile job elapsed time is 2 minutes (maybe 5 for big programs). When the machine is maxed out (CPU at 100%), the very same compile job will typically run anywhere from 3 to 8 HOURS. In other words, there is NO relationship between TCB time of a task and the elapsed time required.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> JCL & VSAM

 


Similar Topics
Topic Forum Replies
No new posts how to send 10 rows at a time to output CICS 2
No new posts is there a way to print time in HH:MM... SYNCSORT 12
No new posts Copy a DS Member to multiple users at... TSO/ISPF 8
No new posts Expected data is not coming up on Fir... CICS 2
No new posts To pull the file with Date and Time u... TSO/ISPF 17
Search our Forums:

Back to Top