Displaying Information About Processes (ps)

You can check the status of active processes on a system by using the ps command. Depending on which options you use, ps reports the following information:

• Current status of the process
• Process ID
• Parent process ID
• User ID
• Scheduling class
• Priority
• Address of the process
• Memory used
• CPU time used

Table 70-1 describes some of the fields reported by the ps command. The fields displayed depend on which option you choose. See the ps(1) man page for a description of all available options.

Table 70-1 ps

Field	Description
UID	The user ID of the process's owner.
PID	The process identification number.
PPID	The parent process's identification number.
C	The processor utilization for scheduling. This field is not displayed when the -c option is used.
CLS	The scheduling class to which the process belongs: real-time, system, or timesharing. This field is included only with the -c option.
PRI	The kernel thread's scheduling priority. Higher numbers mean higher priority.
NI	The process's nice number, which contributes to its scheduling priority. Making a process "nicer" means lowering its priority.
ADDR	The address of the proc structure.
SZ	The virtual address size of the process.
WCHAN	The address of an event or lock for which the process is sleeping.
STIME	The starting time of the process (in hours, minutes, and seconds).

Table 70-1 ps(Continued)

Field	Description
TTY	The terminal from which the process (or its parent) was started. A question mark indicates there is no controlling terminal.
TIME	The total amount of CPU time used by the process since it began.
CMD	The command that generated the process.

· How to List Processes

To list all the processes being executed on a system, use the ps command.

$ ps [-ef]

In this command,

ps	Displays only the processes associated with your login session.
-ef	Displays full information about all the processes being executed on the system.

Example--Listing Processes

The following example shows output from the ps command when no options are used.

$ ps PID TTY TIME COMD 1664 pts/4 0:06 csh 2081 pts/4 0:00 ps

The following example shows output from ps -ef. This shows that the first process executed when the system boots is sched (the swapper) followed by the init process, pageout, and so on.

$ ps -ef UID PID PPID C STIME TTY TIME CMD root 0 0 0 May 05 ? 0:04 sched root 1 0 0 May 05 ? 10:48 /etc/init - root 2 0 0 May 05 ? 0:00 pageout root 3 0 0 May 05 ? 43:21 fsflush root 238 1 0 May 05 ? 0:00 /usr/lib/saf/sac -t 300 root 115 1 0 May 05 ? 0:10 /usr/sbin/rpcbind root 158 1 0 May 05 ? 0:00 /usr/lib/autofs/automountd root 134 1 0 May 05 ? 0:12 /usr/sbin/inetd -s root 107 1 0 May 05 ? 11:49 /usr/sbin/in.routed -q root 117 1 5 May 05 ? 899:32 /usr/sbin/keyserv root 125 1 0 May 05 ? 0:00 /usr/sbin/kerbd root 123 1 0 May 05 ? 4:17 /usr/sbin/nis_cachemgr root 137 1 0 May 05 ? 0:00 /usr/lib/nfs/statd root 139 1 0 May 05 ? 0:02 /usr/lib/nfs/lockd root 159 1 50 May 05 ? 8243:36 /usr/sbin/automount root 199 191 0 May 05 ? 0:00 lpNet root 162 1 0 May 05 ? 0:07 /usr/sbin/syslogd root 181 1 0 May 05 ? 0:03 /usr/sbin/nscd -e passwd,no -e group,no -e hosts,no -f /etc/nscd.conf root 169 1 0 May 05 ? 5:09 /usr/sbin/cron root 191 1 0 May 05 ? 0:00 /usr/lib/lpsched root 210 1 0 May 05 ? 0:01 /usr/sbin/vold root 200 1 0 May 05 ? 0:08 /usr/lib/sendmail -bd -q1h root 4942 1 0 May 17 console 0:00 /usr/lib/saf/ttymon -g -h -p saturn console login: -T AT386 -d /dev/console -l root 208 1 0 May 05 ? 0:00 /usr/lib/utmpd root 241 238 0 May 05 ? 0:00 /usr/lib/saf/ttymon root 5748 134 0 17:09:49 ? 0:01 in.rlogind root 5750 5748 0 17:09:52 pts/0 0:00 -sh root 5770 5750 2 17:23:39 pts/0 0:00 ps -ef

Displaying Information About Processes (/proc Tools)

You can display detailed, technical information about active processes by using some of the process tool commands contained in /usr/proc/bin. Table 70-2 lists these process tools. For more detailed information, refer to the proc(1) man page.

Table 70-2 /usr/proc/bin

Process Tool	What It Displays
pcred	Credentials
pfiles	fstat and fcntl information for open files in a process
pflags	/proc tracing flags, pending and held signals, and other status information
pldd	Dynamic libraries linked into a process
pmap	Address space map
psig	Signal actions
pstack	Hex+symbolic stack trace
ptime	Process time using microstate accounting
ptree	Process trees that contain the process
pwait	Status information after a process terminates
pwdx	Current working directory for a process

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Note - To avoid typing long command names, add the process tool directory to your PATH variable. This enables you to run process tools by entering only the last part of each file name (for example, pwdx instead of /usr/proc/bin/pwdx).

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· How to Display Information About Processes

1. (Optional) Use output from the ps command to obtain the identification number of the process you want to display more information about.

$ ps -e | grep process

In this command,

process........Is the name of the process you want to display more information about.

The process identification number is in the first column of the output.

2. Use the appropriate /usr/bin/proc command to display the information you need.

$ /usr/proc/bin/pcommand PID

In this command,

pcommand	Is the process tool command you want to run. Table 70-2 lists these commands.
PID	Is the identification number of a process.

Examples--Displaying Information About Processes

The following example shows how to use process tool commands to display more information about an lpNet process. First the /usr/proc/bin path is defined to avoid typing long process tool commands. Next, the identification number for lpNet is obtained. Finally, output from three process tool commands is shown.

(1) $ PATH=$PATH:/usr/proc/bin $ export PATH (2) $ ps -e | grep lpNet 191 ? 0:00 lpNet (3) $ pwdx 191 191: /var/spool/lp (4) #$ ptree 191 183 /usr/lib/lpsched 191 lpNet (5) $ pfiles 191 191: lpNet Current rlimit: 1024 file descriptors 0: S_IFCHR mode:0666 dev:102,0 ino:23278 uid:0 gid:3 rdev:13,2 O_RDWR 1: S_IFCHR mode:0666 dev:102,0 ino:23278 uid:0 gid:3 rdev:13,2 O_RDWR 2: S_IFCHR mode:0666 dev:102,0 ino:23278 uid:0 gid:3 rdev:13,2 O_RDWR 3: S_IFIFO mode:0000 dev:159,0 ino:65 uid:0 gid:0 size:0 O_RDWR 4: S_IFREG mode:0666 dev:102,0 ino:14900 uid:0 gid:0 size:105 O_RDWR|O_APPEND 5: S_IFREG mode:0664 dev:102,0 ino:17007 uid:71 gid:8 size:2141 O_RDONLY 6: S_IFIFO mode:0000 dev:159,0 ino:66 uid:0 gid:0 size:0 O_RDWR 7: S_IFIFO mode:0000 dev:159,0 ino:66 uid:0 gid:0 size:0 O_RDWR 8: S_IFIFO mode:0000 dev:159,0 ino:67 uid:0 gid:0 size:0 O_RDWR 9: S_IFIFO mode:0000 dev:159,0 ino:67 uid:0 gid:0 size:0 O_RDWR 10: ??? mode:0444 dev:165,0 ino:2 uid:0 gid:0 size:0 O_RDONLY close-on-exec

(1)

Adds the /usr/proc/bin directory to the PATH variable.

(2)Obtains the process identification number for lpNET.

(3)Displays the current working directory for lpNET. (4) Displays the process tree containing lpNET. (5) Displays fstat and fcntl information.

The following example shows output from the pwait command, which waits until a process terminates, then displays information about what happened. The following example shows output from the pwait command after a Command Tool window was exited.

$ ps -e | grep cmdtool 273 console 0:01 cmdtool 277 console 0:01 cmdtool 281 console 0:01 cmdtool $ pwait -v 281 281: terminated, wait status 0x0000

Controlling Processes (/proc Tools)

You can control some aspects of processes by using some of the process tools contained in /usr/proc/bin. Table 70-3 lists these process tools. For more detailed information, refer to the proc(1) man page.

Table 70-3 /usr/proc/bin

Process Tool	What it Does
pstop	Stops a process
prun	Restarts a process

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Note - To avoid typing long command names, add the process tool directory to your PATH variable. This allows you to run process tools by entering only the last part of each file name (for example, prun instead of /usr/proc/bin/prun).

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· How to Control Processes

1. (Optional) Use output from the ps command to obtain the identification number of the process you want to display more information about.

$ ps -e | grep process

In this command,

process........Is the name of the process you want to display more information about.

The process identification number is in the first column of the output.

2. Use the appropriate /usr/proc/bin command to control the process.

$ /usr/proc/bin/pcommand PID

In this command,

pcommand	Is the process tool command you want to run. Table 70-3 lists these commands.
PID	Is the identification number of a process.

Example--Controlling Processes

The following example shows how to use process tools to stop and restart Print Tool.

(1) $ PATH=$PATH:/usr/proc/bin $ export PATH (2) $ ps -e | grep print* 264 console 0:03 printtoo (3) $ pstop 264 (4) $ prun 264

(1)

Adds the /usr/proc/bin directory to the PATH variable.

(2)Obtains the process identification number for Print Tool.

(3)Stops the Print Tool process. (4)Restarts the Print Tool process.

Killing a Process (kill)

Sometimes it is necessary to stop (kill) a process. The process may be in an endless loop, or you may have started a large job that you want to stop before it is completed. You can kill any process that you own, and root can kill any processes in the system except for those with process IDs 0, 1, 2, 3, and 4.

For detailed information, refer to the kill(1) man page.

· How to Kill a Process

1. (Optional) To kill a process belonging to another user, become root.

2. (Optional) Use output from the ps command to obtain the identification number of the process you want to display more information about.

$ ps -e | grep process

In this command,

process........Is the name of the process you want to display more information about.

The process identification number is in the first column of the output.

3. Use the kill command to stop the process.

$ kill [-9] PID . . .

In this command,

-9	Ensures that the process terminates promptly.
PID . . .	Is the ID of the process or processes to stop.

Verification--Killing a Process

Use the ps command to be sure that the process has been stopped.

Managing Process Class Information

The listing below shows which classes are configured on your system, and the user priority range for the timesharing class. The possible classes are:

• System (SYS)
• Interactive (IA)
• Real-time (RT)
• Timesharing (TS)

  · The user-supplied priority ranges from -20 to +20.

  · The priority of a process is inherited from the parent process. This is referred to as the user-mode priority.

  · The system looks up the user-mode priority in the timesharing dispatch parameter table and adds in any nice or priocntl (user-supplied) priority to and ensures a 0-59 range to create a global priority.

· How to Display Basic Information About Process Classes

You can display process class and scheduling parameters with the priocntl -l command.

$ priocntl -l

Example--Getting Basic Information About Process Classes

The following example shows output from the priocntl -l command.

$ priocntl -l CONFIGURED CLASSES ================== SYS (System Class) TS (Time Sharing) Configured TS User Priority Range: -20 through 20

· How to Display the Global Priority of a Process

You can display the global priority of a process by using the ps command.

$ ps -ecl

The global priority is listed under the PRI column.

Example--Displaying the Global Priority of a Process

The following example shows output from ps -ecl. Data in the PRI column show that pageout has the highest priority, while sh has the lowest.

# ps -ecl F S UID PID PPID CLS PRI ADDR SZ WCHAN TTY TIME COMD 19 T 0 0 0 SYS 96 f00d05a8 0 ? 0:03 sched 8 S 0 1 0 TS 50 ff0f4678 185 ff0f4848 ? 36:51 init 19 S 0 2 0 SYS 98 ff0f4018 0 f00c645c ? 0:01 pageout 19 S 0 3 0 SYS 60 ff0f5998 0 f00d0c68 ? 241:01 fsflush 8 S 0 269 1 TS 58 ff0f5338 303 ff49837e ? 0:07 sac 8 S 0 204 1 TS 43 ff2f6008 50 ff2f606e console 0:02 sh

· How to Designate Priority

1. Become root.

2. Start a process with a designated priority.

# priocntl -e -c class -m userlimit -p pri command_name

In this command,

-e	Executes the command.
-c class	Specifies the class within which to run the process. The default classes are TS (timesharing) or RT (real-time).
-m userlimit	Specifies the maximum amount you can raise or lower your priority, when using the -p option.

-p pri command_name Lets you specify the relative priority in the RT

class, for a real-time thread. For a timesharing process, the -p option lets you specify the user-supplied priority which ranges from -20 to +20.

Example--Designating a Priority

The following example starts the find command with the highest possible user-supplied priority.

# priocntl -e -c TS -m 20 -p 20 find . -name core -print

· How to Change Scheduling Parameters of a Timeshare Process

1. Become root.

2. Change the scheduling parameter of a running timeshare process.

# priocntl -s -m userlimit [-p userpriority] -i idtype idlist

In this command,

-s	Lets you set the upper limit on the user priority range and change the current priority.
-m userlimit	Specifies the maximum amount you can raise or lower your priority, when using the -p option.
-p userpriority	Allows you to designate a priority.

-i idtype idlist Uses a combination of idtype and idlist to identify the process. The idtype specifies the type of ID, such as PID or UID.

Example--Changing Scheduling Parameters of a Timeshare Process

The following example executes a command with a 500-millisecond time slice, a priority of 20 in the RT class, and a global priority of 120.

# priocntl -e -c RT -t 500 -p 20 myprog

· How to Change the Class of a Process

1. (Optional) Become root.

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Note - You must be root or working in a real-time shell to change processes from, or to, real-time processes.

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2. Change the class of a process.

# priocntl -s -c class -i idtype idlist

In this command,

-s	Lets you set the upper limit on the user priority range and change the current priority.
-c class	Specifies the class, TS or RT, to which you are changing the process.

-i idtype idlist Uses a combination of idtype and idlist to identify the process. The idtype specifies the type of ID, such as PID or UID.

Example--Changing the Class of a Process

The following example changes all the processes belonging to user 15249 to real-time processes.

# priocntl -s -c RT -i uid 15249

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Note - If, as root, you change a user process to the real-time class, the user cannot subsequently change the real-time scheduling parameters (using priocntl -s).

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· How to Change the Priority of a Process

You can raise or lower the priority of a command or a process by changing the nice number. To lower the priority of a process:

/usr/bin/nice command_name	Increase the nice number by four units (the default)
/usr/bin/nice +4 command_name	Increase the nice number by four units
/usr/bin/nice -10 command_name	Increase the nice number by ten units

The first command increases the nice number by four units (the default); and the second command increases the nice by ten units, lowering the priority of the process.

The following commands raise the priority of the command by lowering the nice number.

To raise the priority of a process:

/usr/bin/nice -10 command_name	Raises the priority of the command by lowering the nice number
/usr/bin/nice - -10 command_name	Raises the priority of the command by lowering the nice number. The first minus sign is the option sign, and the second minus sign indicates a negative number.

The above commands raise the priority of the command, command_name, by lowering the nice number. Note that in the second case, the two minus signs are required.