Re: Timeslice recommendations

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Eric,

My apologies for not responding sooner.  I have been too busy to process list 
messages (I have 
872 to go through ... aaarrrrgggh!)

The simple starting point is to multiply the existing values by .1 (or divide 
by 10).  2000 
becomes 200, 5000 becomes 500.  I would then evaluate the result.  A more 
accurate interactive 
value can be determined by running the performance tools for a typical period 
and printing the
System Report.  The 'Resource Utilisation' page will show you the average 
interactive CPU per 
transaction -- where a transaction is the processing resulting from an AID key 
being pressed.  
Use this value + 10% and monitor the effect of the change.

Batch job values are a little harder to determine and I generally start by 
lowering the batch 
timeslice to the maximum response time your interactive users will accept. That 
means any 
run-away batch job will only get that much time at the CPU before being kicked 
out and thus 
give an interactive job a chance.  This value is usually greater than the value 
for interactive 
jobs.  For example, if your users scream when interactive response exceeds 2 
seconds then set 
the timeslice for batch to 1800 although you may find that the 500 value 
mentioned above is 
adequate.

You will need to experiment somewhat with the actual values depending on your 
particular system 
configuration and workload.  It is quite possible for some of the larger 
systems to operate 
very well with 2 digit timeslice values.

You will need to compromise based on what you primary goal is: Excellent 
interactive response; 
maximum batch through-put; etc.

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> X-Mailer: ccMail Link to SMTP R8.10.00
> MIME-Version: 1.0
> Date: Thu, 08 Apr 99 09:52:18 -0600
> From: eric.delong@pmsi-services.com
> To: midrange-l@midrange.com
> Reply-To: MIDRANGE-L@midrange.com
> Subject: Timeslice recommendations

> 
> R
>      Simon, 
>      
>      Some time ago, you posted the following:
>      
>      "Also the default timeslice values of 2000 and 5000 are 
>      generally far too large for the faster hardware (and 
>      that includes all RISC systems) -- especially for 
>      interactive jobs.
>      
>      Regards,
>      Simon Coulter."
>      
>      What are you recommendations for user class objects on RISC? 
>      
>      tia
>      eric.delong@pmsi-services.com
>      
> 
> 
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