For a discussion of the !OBITOR command options, see the !!L370 The for".at of the Class I and E !ONITOB co •• and is: ftOBitor Display ENable INTerval
r , ITIPE I IILL I L .J , PERF ora \ RESPonse I SCHedule USER INSTsi. DIStap SEEKs SYSprof 1
r ,
nnnnn IMINI L .J
r STArt [to userid] [BUFFS n] I ITIPE I I I ICPTRICE L
r , STOP I SPOOL I tTIPE I ICPTRICEI L .J CLOSE IUTOdisk JON } lOFF r ,
raddr I !ODE { aOO} I I 1600 I [BUFFS I 6250 I L .J TIME {
FROP.! FOR ALL HONE b 1 : III TO h 2 : .2 }
bh:m.
r , LIP.!IT n ISTOP I ISI!PLEI L .J SEEKS {
INclude
EXclude
DELete DISplay raddr raddr ••• }
raddr raddr ••• , " I I I n]l I I I .J lSelect one or aore of the classes, subject to the restrictions listed
with the ENIBLE operand. Section 3. CP Co •• ands 95

DISPLAY ERABLE PERFORlt r , ISPOOLI ITAPE I IALL I L .J
displays the status of the pertinent Vlt/370 ltonitor variables and the status of the internal trace table. SPOO!. is the default operand.
class of monitor is listed.
Regardless of the oFerand you select, each
call and its current enabled/disabled state
If SPOOL is specified, the automatic monitoring specifications
are listed, including whether or not automatic monitoring has
been requested, its start and stop times, the number of
monitor buffers to be used, the userid of the virtual machine to receive the spool file, the spool file record liait and
class, and which classes of monitoring are to be enabled.
If automatic monitoring is already in progress, the spool file
nuaber is given together with the number of monitor buffer
records already written to it.
If the TAPE option is requested, only the status of .onitor
classes and CPTRACE table is indicated.
If ALL is specified, a combination of SPOOL and TAPE responses
is given. enables the specified classes of !ONITOR CALL. Each
successful coapletion of this command creates a new value for
control register 8. The effect of the MONITOR ENABLE command varies, depending on whether data collection is active or
inactive when the co.mand is issued. If data collection is
active, the new mask is moved directly into control register
8, replacing the previous mask, and the new aask takes effect
imaediately. Collection then continues the classes just
entered. If data collection is not active, the new mask is
saved, and data collection of the specified classes does not begin until a ItOB:tTOR START is issued. samples systea resource usage data by accessing system
counters of interest to system performance analysts. RESPONSE collects data on terainal I/O. Simplifies analysis of co.aand
usage, user response time, and system response time. It can
relate user activity to system performance. This class is
invalid and no data can be collected for it unless the system program.er changes the LOCAL COpy file and reassembles D!K!CC. SCHEDULE collects data about scheduler queue manipulation. ltonitors flow of work througb the system
6 and indicates the
resource allocation strategies of the scheduler, which is one
of the key functions of the system. USER periodically scans the chain of V!BLOKs in the system, and
extracts user resource utilization and status data. lISTSI! records every virtual aachine privileged instruction handled by the control program (CP). Because siaulation of privileged
instructions is a major source of overhead, this data may lead
to aethods of iaproving performance. If the VltA feature is
96 V8/370 Operator's Guide