Date:         Wed, 8 Sep 2004 13:00:56 -0500
Reply-To:     "Dunn, Toby" <Toby.Dunn@TEA.STATE.TX.US>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Dunn, Toby" <Toby.Dunn@TEA.STATE.TX.US>
Subject:      Re: how to increase performance in this case?
Comments: To: Igor Kurbeko <ikurbeko@ATHEROGENICS.COM>
Content-Type: text/plain; charset="us-ascii"

Igor,

From the v9 help docs:

Real time represents the clock time it took to execute a job or step; it
is heavily dependent on the capacity of the system and the current load.
As more users share a particular resource, less of that resource is
available to you. CPU time represents the actual processing time
required by the CPU to execute the job, exclusive of capacity and load
factors. If you must wait longer for a resource, your CPU time will not
increase, but your real time will increase. It is not advisable to use
real time as the only criterion for the efficiency of your program
because you cannot always control the capacity and load demands on your
system. A more accurate assessment of system performance is CPU time,
which decreases more predictably as you modify your program to become
more efficient.


Unless you are really pushed for resources I would leave your code alone
real time           33.32 seconds
cpu time            4.60 seconds
Doesn't seem to bad too me.

Toby Dunn

-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of
Igor Kurbeko
Sent: Wednesday, September 08, 2004 12:51 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: how to increase performance in this case?

Hi.



I run the following code;



Data final;

Set _a271 _a301 _a421;

Run;



It takes 33 seconds. Thou the CPU time is only 4.6 seconds.

What's the difference between CPU and REAL time?

Does anybody know how to decrease time?





NOTE: There were 20632 observations read from the data set WORK._A271.

NOTE: There were 29960 observations read from the data set WORK._A301.

NOTE: There were 55971 observations read from the data set WORK._A421.

NOTE: The data set WORK.DSN has 106563 observations and 50 variables.

NOTE: DATA statement used:

      real time           33.32 seconds

      cpu time            4.60 seconds



If use datasets from the permanent librayr vs. WORK it takes much less
time





Igor Kurbeko

Clinical Programmer Analyst

678 336 4328

ikurbeko@atherogenics.com



Imagination is more important than knowledge