The STATS processor CPU display provides an overal I snapshot of what is happening in the system. The STATS RESPONSE histogram is used as detailed information to help in setting the CPU tuning parameters.
STATS CPU Display
An example of a STATS CPU display is shown in the following figure.
STATS interval from 08:08:36.94 to 15:39:12.98
I a"
I
Isnapt I a IIf
IsnaplX batch execution 10.3 31. 7 ET~F 1 1
X batch service 17.5 30.2 9ex response time 50 50
X online execution 3.8 37.0 I/O load factor 10 8
X online service 8.7 90.3
i
of botch u.er. 0 4X ghost execution 6.9 26.0 of online users 7 55
X ghost service 9.9 30.4 of ghost users 18 19
X TP execution 0.0 0.0 , of TP users 0 2
X TP service 0.0 0.0 I/Os per minute 682 2876
X monitor execution 4.4 17.3 Schedules per minute 708 3244
X I/O wait 23.4 20.1 Interactions per min 12 105
X resource wait 0.0 0.1 Events per minute 1371 5814
X I/Otresource wait 0.0 0.1 PMMEs per minute 8002 36902
X true idle 214.0 9.6 Avg. usec per ~E 2813 2561
Total 300.9 300.3 ~inutes in interval 6517 451
Figure 11. STATS CPU Display
When tuning a system. the system manger should use the STATS processor GLOM command to perform data reduction and examine the statistics in the snap column of the data
reduction. These statistics are the averages of the workload for the selected period.
The statistics in the all column are the averages of the workload since the system was last booted. Since the 01 I column may contain the statistics from several distinct periods. in most cases the all statistics are not used to make system tuning decisions.
The system manager should examine the percentages in the first eight lines of the left side of the display and the number of users in each mode to determine whether each CP-6 access mode is getting the correct total percentage of the CPU for the period spanned by the statistics.
The following table defines the items in a STATS CPU display.
132 STATS CPU Display CE68-80
Module 6-3
Display Entry X mode execution
X mode service
X monitor execution
x
I/O waitX resource wait
x
I/O resource waitCE60-00
Table 8. STATS CPU Display Definitions Definition
The percentage of CPU time spent executing user code in each mode. The mode is specified as either batch. online.
ghost. or TP. This percentage is directly chargeable to users in the form of CPU execution time.
The percentage of CPU time spent executing monitor code to satisfy user monitor service requests. The mode is
specified as batch. online. ghost. or TP. This percentage is directly chargeable to users in the form of CPU service time.
The percentage of CPU time spent executing monitor code for internal monitor functions (e.g .• scheduling. interrupt handling. etc.). This percentage of the CPU time is the monitor overhead.
The percentage of CPU time spent idle waiting for I/O operations to complete. If the system did not have to go
into an idle state waiting for I/O to complete. this percentage wil I be zero.
The percentage of CPU time spent idle waiting for an internal monitor resource to become available. If the system did not have to go into an idle state waiting for an internal monitor resource to become available. this
percentage wil I be zero.
The percentage of CPU time spent idle waiting for I/O to complete or for an internal monitor resource to become avai lable. If the system did not have to go into an idle state waiting for an I/O to complete or an internal monitor resource to become avai lable. this percentage wil I be zero.
STATS CPU Display Module 6-3
133
Display Entry
~ true idle
ETMf
9ex response time
I/O load factor
, of mode users
134
Table 8. STATS CPU Display Definitions (cont.) Definition
The percentage of CPU time that was spent idle with nothing to do.
Execution time multiplication factor. This factor is multipl ied times the required CPU time to give an estimate of how much elapsed time will be required to execute a task. for example, if a task requires 2 CPU minutes and the ETMf is 3, then the task wil I require approximately 6 minutes of elapsed time to complete.
The time in mil I iseconds between the receipt of an activation character (normally a carriage return) by the host and the start of processing for 9ex of the activation characters received. The 9~ response time is calculated only for online users. Note that this is not the response time from last character entered to first character
received, and does not include delays in the FEP.
This factor is the measure of the I/O load on the system.
This factor is the probability that on I/O request will be queued rather than executed immediately. This number is the overage of the I/O load factors of all devices active during the interval.
The number of users on the system for eoch mode. The mode is specified as batch, online, ghost or TP. For a GO or REPLAY command, the number in the snap column is the number of users on the system in the respective mode at the end of the interval. The number in the all column is the overage number of usera on the syst.- in the respective mode since the last system boot or recovery. For a GLOM command, each column is the overage number of users on the system in the
respective mode during the interval specified in each column.
STATS CPU Display Module 6-3
CE60-88
Table 8. STATS CPU Display Definitions (cont.) Display Entry
I/Os per minute
Schedules per minute
Interactions per min
Events per minute
PMMEs per minute
Avg. usec per PMME
Minutes in interval
CE60-80
Definition
The number of I/O connects per minute to al 110M-connected controllers and system consoles. Each connect may contain several I/O commands for the controller.
The number of passes per minute through the system scheduler. The number of schedules per minute is
influenced by the number of I/Os per minute, the number of interactions per minute, and tuning parameters.
The number of activation characters (e.g., carriage return, line feed, etc.) received by the host per minute.
The number of scheduler events that occurred per minute.
The number of monitor service requests per minute. Every monitor service request is a Privileged Master Mode Entry (PMME) CLIMB instruction.
The average number of microseconds required to complete the monitor service request.
The number of minutes in the interval. The al I column contains the number of minutes since the last system boot or recovery. The snap columns contains the number of minutes in the interval of the INT or GLOM command.
STATS CPU Disploy Module 6-3
135
ST A TS RESPONSE Hstogram
The STATS RESPONSE histogram provides detailed information about the interactive response time for online users. The following figure is an example of the STATS RESPONSE histogram.
STATS interval from 08:08:36.94 to 15:39:12.98
"Snap" histogram of interactive response time (mi I I iseconds)
Figure 12. STATS RESPONSE Histogram
7885 interaction that occurred during the requested interval.
This histogram provides: