SYSP!ON P!acro r , I CL ASS=P! I I CL ASS=class I L .J
specifies the spool file to be generated to contain monitor data.
Any valid class (A through Z and 0 through 9) may be used but the
default P! is preferred since the VP!AP data reduction Field
Developed Program is designed to reduce only spool files of that
class.
r , I AUTO=NO I I AUTO=YES I L .J
specifies whether or not automatic monitoring should take place
according to the rema1n1ng SYSP!ON parameter specifications. The default, NO, requires the installation to make a specific change to
cause automatic monitoring. All other parameters may be system
default values, giving positive and useful monitoring results.
r , IENABLE=(PERFORM,USER,DASTAP) , lENABLE=(classa,classb,classc, ••• ) , L .J
specifies any combination of valid monitor classes of data
collection. It is assumed that the system analyst understands the
use of the various classes, the overhead incurred in data
collection, and the relative magnitude of the corresponding data
reduction. The default specifies sampled data classes only and are
considered minimal for useful data reduction. The default classes
are sufficient for analysis of a system's load environment and
performance profile with a view to diagnosis of possible bottleneCKS and for establishing long term growth trends.
r , lTIP!E=(09:00,17:00) , I TIM E= (h 1 : m 1 , h 2 : m 2) I ITIP!E=ALL , lTIME=NONE I L .J
specifies the time period in each day that automatic monitoring
(performance data collection) should take place. This parameter
may indicate a start and stop time in hours and minutes using a
24-hour clock; continuous monitoring (if ALL is specified) or no
monitoring (if NONE is specified) unless the operator or system
analyst overrides this specification with the PlONITOR command. If
a system restart occurs during an automatic monitoring period, the
old spool file is closed out and a new one is started, according to
the 5YSMON specifications. For useful data reduction, several
hours of monitoring is suggested.
Note: This same closeout occurs at midnight if ALL is specified.
r , I LIMIT= (50000, NOSTOP) I ILIP!IT=(limit,STOP) I I LIMIT= (limit, NOSTOP) , I LIMIT= (limit, SAMPLE) I L .J
specifies the maximum number of monitor record buffers that can be
added to the monitor spool file before it is closed, whether or not
monitoring should be terminated when the limit is reached or the
periodic closing of the monitor spool file after a specified number
of samples (also defined by the value of LIPlIT) have been
collected. This parameter gives the installation more control over 1
7 8 IBP! VM/370 Planning and System Generation Guide

SYSMON Macro the amount of spool space that can be used by the automatic
monitoring facility. It can also be used to create several small
monitor spool files, rather than one large file and, for instance,
give the data reduction facility an opportunity to start processing
the morning's data while collecting the afternoon's data. 'limit'
can be any decimal number between 10 and 50000. When determining
the value for 'limit', take into consideration the classes of data
collection enabled, the size of the associated records, the
sampling interval and remember that each monitor buffer contains
approximately 4000 bytes of data space.
Specifying SAMPLE allows the installation analyst t6 define the
rate at which spool files will be produced. Since sampled data is
collected at very precise intervals of time, according to the value
specified in the MONITOR INTERVAL command (default 60 seconds), the
spool file may be consistently and repeatedly closed. Monitor spool
files obtained in this manner contain performance data covering
consecutive, and equal intervals of time and containing the same number of PERFORM, DASTAP, and, possibly, USER (if no users logged
on or off) records. This capability could form the basis of a real
time performance analysis facility.
r , IBUFFS=cpu defaultl I BUFFS=n 1
L J specifies the number of data collection buffers needed by the
monitor to avoid suspension occurrences. Data collection
suspension occurs when output to tape or spool files cannot keep
ahead of the collection of data and an overrun condition occurs. By increasing the number of monitor buffers the suspension
occurrences can be reduced or eliminated. The default depends on
the processor on which the system is running. (See the VM/37Q description of the MONITOR command.) If
the user is not satisfied with the defaults, he may specify any
number of buffers from 1 to 10. SYSMON USERID=ANALYST,AUTO=YES,ENABLE=(PERFORM), TIME=ALL,BUFFS=l x
This example specifies automatic monitoring for 24 hours a day using
only the PERFORM class of data collection and one buffer. The spool
file created is practically unlimited in size, taking the 50000 default
and will be sent to the ANALYST virtual machine's reader each midnight
or at system restart or shutdown. The spool file class is the default M. !Q!e: All of the above automatic monitoring specifications may be
overridden by the operator or system analyst using the MONITOR command. Part 2. Defining Your VM/370 System 179