The SHOT Tool
SHOT provides information on what processes are active on the machine. It provides a
snapSHOT of process activity, and allows the priority of processes to be adjusted. SHOT can also
be used to alter the state of a process.
Operation
SHOT's primary purpose is to show you processes that are interesting. At startup, "interesting" is
defined as "processes that have used CPU since the last time you hit Return". This is called the
DELTA command, and is executed by default when you hit Return. Thus, if you run SHOT and
then just hit Return, Return, ..., each time SHOT will show you the processes that have used
some CPU since the prior Return. See SHOT’s ADM command and Process-Display section for
details.
Viewing System Activity
The display of just CPU-using processes is called a "delta" display. (The "delta", or difference
between the current CPU usage and the prior CPU usage is non-0.)
The ALL command displays all processes, regardless of their CPU usage.
You can restrict the display of active processes shown by the delta command in several ways:
only show processes using more than a specified percentage of the CPU (use: %n i.e.,: %5 will only show processes that have used at least 5% of a CPU in the recent interval)
exclude specified PINs (via the EXCLUDEPINS command)
exclude processes waiting on specified wait events (i.e., EXCLUDEWAITS BREAK)
The "TREE" command shows all processes, according to their tree structure (parent/child), and
ignores exclusion rules.
In the DELTA and ALL commands, the format of the output can be controlled via the ADM
(Automatic Display Mode) command. For example, you can add a column to show the number of
transient disk pages used by a process by saying: ADM + SECPAGES
The command ADM ? will list all available ADM fields.
The HIGHLIGHT command can be used to tell SHOT to highlight certain processes (i.e.,
HIGHLIGHT USER @.SYS)
You can control a process using:
ABORTCONNS, ABORTPROCIO, BREAK, KILL, PRIORITY, RESUME, SUSPEND
You can get information about a single process using:
ANCESTORS, CPU, DAD, FAMILY, JS, PIN, TP, TRACE, TREE
In addition to showing processes, SHOT has several other kinds of displays it can do:
display jobs and/or sessions
display job/session tables (JOBINFO)
display jobqueue information (LISTJOBQ)
display a list of different programs currently running (and the number of processes using each program)
report system uptime (UPTIME)
display a summary of why processes are waiting (SUMWAIT)
display information about locked SIRs
display information about PIN and VSM tables (TABLES).
Altering System Activity
In addition to viewing process information, you can alter some aspects of process activity. SHOT’s
BREAK and RESUME commands are used to suspend and reactivate processes by PIN. The
PRIORITY command is used to change the CPU queue in which a process is executing.
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NOTE Placing a process in the A or B queue could "take over" the system and cause a system halt. The A and B queues are typically only used by system processes.
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SHOT’s KILL command is used for terminating a single process. The KILL command is especially
useful for processes which seem to be "hung".
Capabilities
Program capabilities include IA, BA, PM, DS and PH. User PM capability is required to use the
STACK TRACE or DEBUG commands. User SM is required to use the ABORTCONNS,
ABORTPROCIO, BREAK, RESUME or KILL commands. OP, SM or PM is required to use the
PRIORITY command.
Usage
SHOT can be run either from the supplied UDC or from a fully-qualified RUN statement.
SHOT <command>
RUN SHOT.PUB.LPSTOOLS;INFO=“<command>”
When you run SHOT with a command parameter, it executes that command and then
automatically terminates.
The SHOT Process Display
The SHOT display is something you’ll want to know about in order to understand the information
being presented. This section explains the display components. The first line is a Time & Date
header, and it is followed with several user-selectable fields. The following section describes
these fields in detail.
The header for the default display format for SHOT is:
Figure 16.1 SHOT - Header for the default display format
Display column: ?
ADM field: STATE
The Process State is denoted by a question mark (?) in the SHOT header line. This shows the
state of a process when the state is something other than alive.
The Process State are described in the next table:
Table 16.1 SHOT - Process States
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Character
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State
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Description
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?
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unknown
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PCB for process has not been allocated
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d
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dying
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Process is beginning to terminate
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x
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dead
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Process terminated, PCB not deallocated
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<blank>
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alive
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Process is running
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i
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initiating
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Process being born
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u
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unborn
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Process just started being created
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Display column: Pin
ADM field: PIN
The PIN is the Process Identification Number for a process. This is a 16-bit number which is
reused when a process terminates.
See also: PID
Display column: CPU
ADM field: CPU
The CPU column reports the total processor time (CPU) used by a process since it started. The
values shown are usually in milliseconds, but will have a letter prefix if they have used more CPU
than can be displayed without overflowing the column width (which defaults to 6 characters, or
999,999 milliseconds). The prefixes are: s for seconds, m for minutes, h for hours, D for days, and
W for weeks.
Display column: Process Name
ADM field: NAME
The Process Name column shows the name of the process running. The majority of processes
are programs (files with filecode of PROG or NMPRG) that were :RUN (or started with the
CREATE or CREATEPROCESS intrinsic). A few processes are started by privileged code
pointing to a procedure in either NL.PUB.SYS or SL.PUB.SYS and saying: Start!. These
processes are referred to as being procreated. These processes do not have normal names (i.e.:
EDITOR.PUB.SYS) because there is no associated program file. SHOT tries to determines the
name of the original procedure that was started and, if successful, displays the first 32 characters
(or so) of the procedure name. If unsuccessful, the procedure address is shown in hexadecimal
as a space and offset (i.e.: $a.4b2d90).
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NOTE SHOT is unable to determine the names of procedures started from SL.PUB.SYS. It indicates these as (CM Procedure).
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Display column: Pri
ADM field: PRI
The Pri column shows the current priority of a process. The priority is a value in the range 0..255,
with 0 being the highest priority. The CI's :SHOWQ command reports the base and limit priority
values for the C, D, and E scheduling queues.
Display column: Q
ADM field: QUEUE
The Q column reports what scheduling queue a process is in.
The possible queues are:
Table 16.2 Queue Codes
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Code
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Description
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A
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Process is in the A subqueue
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B
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Process is in the B subqueue
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C
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Process is in the C subqueue
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D
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Process is in the D subqueue
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E
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Process is in the E subqueue
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NOTE As of MPE XL 2.1, it is possible to put a process into four apparently new queues called BM, CM, DM, and EM. In fact, MPE does not have four new queues. Instead, when a process is placed into one of these queues (with the ALTPROC command), it is simply placed at the base of the BS, CS, DS, or ES queue and is marked as a system process so that its priority will not degrade over time.
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Display column: Delta
ADM field: DELTA
The Delta column shows the amount of CPU used by a process since the last time a process
display was shown. The values in this field are typically in milliseconds, but will have a suffix of s
for seconds, m for minutes, h for hours, D for days, and W for weeks.
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NOTE The CPU delta value for JSMAIN processes (those that are JSMAIN.PUB.SYS) will sometimes be negative. Whenever a job or session starts (and runs), it is assigned a JSMAIN process, which will use a small amount of CPU time in getting the job or session started. When the job or session terminates, the JSMAIN process uses a little more CPU time, but then sometimes stays around in idle mode, waiting to be assigned to a new job or session. When JOB.PUB.SYS (the parent of all jobs) or SESSION.PUB.SYS (the parent of all sessions) chooses that JSMAIN for a new job or session, JOB or SESSION resets the JSMAIN's total CPU time counter back to about 1/2 second of CPU. If SHOT noted the CPU total for a JSMAIN before and after this reset, the process will look like it used a negative amount of CPU time!
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Display column: %
ADM field: PERCENT
The % column shows the approximate percentage of available CPU that a process has used
since the last time a process display was shown. Due to the way SHOT determines CPU usage, it
is possible that the sum of all percentages shown might exceed 100%, particularly if the previous
process display was done very recently.
Display column: Ic
ADM field: EXECMODE
The Ic column shows the Initial and Current modes for a program. The first character of this
column is: C, N, O, or P. The second character of this column is: n or c.
Table 16.3 Execution Mode Codes
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Code
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Description
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Cn
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Process is a Compatibility Mode program, currently in Native Mode
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Cc
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Process is a Compatibility Mode program, currently in Compatibility Mode
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Nn
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Process is a Native Mode program, currently in Native Mode
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Nc
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Process is a Native Mode program, currently in Compatibility Mode
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Oc
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Process is a Compatibility Mode program (OCT’ed), currently in Compatibility Mode
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On
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Process is a Compatibility Mode program (OCT’ed), currently in Native Mode
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Pn
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Process is a POSIX Native Mode program, currently in Native Mode
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Pc
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Process is a POSIX Native Mode program, currently in Compatibility Mode
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NOTE Processes that are procreated native mode procedures will have an n instead of N in the Initial column
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Display column: Wait State
ADM field: WAIT
The Wait State column reports why a process is waiting. On a single CPU machine, every
process (except SHOT itself) should either be waiting for something to happen (i.e.: a page to be
read from disc) or should be READY to run. On a multiple CPU machine, several processes (in
addition to SHOT) might be EXECUTING at the same time.
The following is in order of ADm field names (except the fields from the default display format,
explained above).
Display column: BlkR
ADM field: BLOCKEDR
The BlkR column shows the numeric code indicating why a process is blocked (if it is), called the
blocked reason. The same information is usually available in pseudo-english in the WAIT column.
Display column: Caps
ADM field: CAPABILITY
The Caps column shows the capability mask for a process. This is a 32-bit value, with bits
meaning:
Table 16.4 Capability Bits
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Cap
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Bit#
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Meaning (if bit on)
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SM
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0
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System Manager
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AM
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1
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Account Manager
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AL
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2
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Account Librarian
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GL
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3
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Group Librarian
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DI
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4
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Diagnostician
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OP
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5
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Operator
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CV
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6
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Create Volumes
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UV
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7
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Use Volumes
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LG
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8
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User Logging
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SP
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9
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System process handling
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PS
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10
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Programatic Sessions
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NA
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11
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Network Administrator
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NM
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12
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Node Manager
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CS
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13
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Communication Subsystem
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ND
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14
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Use Non-Sharable devices
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SF
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15
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Save Files
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..
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16..22
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(reserved)
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BA
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23
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BAtch access
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Display column: StXDS
ADM field: CMSTACK
The StXDS column reports various values for the Compatibility Mode (CM) environment of a
process. If width permits, the following is shown:
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DBXDS
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is the Data Segment number of the Compatibility Mode DB (usually the same as the CM Stack, unless in split-stack mode).
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StXDS
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is the Data Segment number of the CM Stack.
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S
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is the top-of-CM-stack register. This may not be accurate for processes currently executing on another CPU.
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Z
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is the limit-of-CM-stack register.
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Display column: S Z
ADM field: CMSZ
The S Z column reports the value for the CM S and Z registers of a process. It is a subset of the
information provided by the ADM-CMSTACK field.
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S
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is the top-of-CM-stack register. This may not be accurate for processes currently executing on another CPU.
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Z
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is the limit-of-CM-stack register.
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Display column: Cflts
ADM field: CFAULTS
The Cflts column shows the total number of code page faults for each process. A code page
fault was an attempt to access an instruction, but the virtual page was not in memory.
Display column: CMTIME
ADM field: CMTIME
The CMTIME column reports the total processor time (CPU) used by a process while in CM
(Compatibility Mode).
See ADM-CPU for a description of the display format.
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NOTE The CMTIME value is tracked only while the Measurement Interface (MI) is enabled. SHOT does not enable the MI. SOS/3000 and Glance/XL are examples of performance tools that enable the Measurement Interface.
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Display column: C
ADM field: CRITICAL
The C column shows the depth of nesting in critical mode for each process. A non-critical
process will have a blank in this column.
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NOTE Processes that are critical (have a non-0 value here) will ignore :ABORT, :ABORTJOB, and other KILL requests until they become non-critical.
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Display column: Dbg
ADM field: DEBUG
The Dbg column has a Yes for each process that has the ;DEBUG flag on. Normally, if a program
is run with ;DEBUG, the bit is on. However, MPE/iX seems to set this bit for a few other processes
for undetermined reasons.
Display column: DelCFl
ADM field: DELCFAULTS
The DelCFl column shows the number of code page faults for each process since the last display.
Del is short for Delta.
Display column: DelDFl
ADM field: DELDFAULTS
The DelDFl column shows the number of data page faults for each process since the last display.
Del is short for Delta.
Display column: DelFl
ADM field: DELDFAULTS
The DelDFl column shows the number of data page faults for each process since the last display.
Del is short for Delta.
Display column: Dflts
ADM field: DFAULTS
