How to Use prctl to Temporarily Change a Value

This example procedure uses the prctl command to temporarily add a new privileged value to deny the use of more than three LWPs per project for the x-files project. The result is comparable to the result in How to Set the Maximum Number of LWPs for Each Task in a Project.

1. Become superuser or assume an equivalent role.

   Roles contain authorizations and privileged commands. For more information about roles, see "Using the Solaris Management Tools With RBAC (Task Map)" in System Administration Guide: Basic Administration.

2. Use newtask to join the x-files project.

   # newtask -p x-files

   
   

3. Use the id command with the -p option to verify that the correct project has been joined.

   # id -p uid=0(root) gid=1(other) projid=101(x-files)

   
   

4. Add a new privileged value for project.max-lwps that limits the number of LWPs to three.

   # prctl -n project.max-lwps -t privileged -v 3 -e deny -i project x-files

   
   

5. Verify the result.

   # prctl -n project.max-lwps -i project x-files process: 111108: csh NAME PRIVILEGE VALUE FLAG ACTION RECIPIENT project.max-lwps privileged 3 - deny - system 2.15G max deny -

   
   

How to Use prctl to Lower a Resource Control Value

1. Become superuser or assume an equivalent role.

   Roles contain authorizations and privileged commands. For more information about roles, see "Using the Solaris Management Tools With RBAC (Task Map)" in System Administration Guide: Basic Administration.

2. Use the prctl command with the -r option to change the lowest value of the process.max-file-descriptor resource control.

   # prctl -n process.max-file-descriptor -r -v 128 $$

   
   

How to Use prctl to Display, Replace, and Verify the Value of a Control on a Project

1. Become superuser or assume an equivalent role.

   Roles contain authorizations and privileged commands. For more information about roles, see "Using the Solaris Management Tools With RBAC (Task Map)" in System Administration Guide: Basic Administration.

2. Display the value of project.cpu-shares in the project group.staff.

   # prctl -n project.cpu-shares -i project group.staff project: 2: group.staff NAME PRIVILEGE VALUE FLAG ACTION RECIPIENT project.cpu-shares privileged 1 - none - system 65.5K max none

   
   

3. Replace the current project.cpu-shares value 1 with the value 10.

   # prctl -n project.cpu-shares -v 10 -r -i project group.staff

   
   

4. Display the value of project.cpu-shares in the project group.staff.

   # prctl -n project.cpu-shares -i project group.staff project: 2: group.staff NAME PRIVILEGE VALUE FLAG ACTION RECIPIENT project.cpu-shares privileged 10 - none - system 65.5K max none

   
   

Using rctladm

How to Use rctladm

Use the rctladm command to make runtime interrogations of and modifications to the global state of the resource controls facility. See the rctladm(1M) man page for more information.

For example, you can use rctladm with the -e option to enable the global syslog attribute of a resource control. When the control is exceeded, notification is logged at the specified syslog level. To enable the global syslog attribute of process.max-file-descriptor, type the following:

# rctladm -e syslog process.max-file-descriptor

When used without arguments, the rctladm command displays the global flags, including the global type flag, for each resource control.

# rctladm
process.max-port-events     syslog=off  [ deny count ]
process.max-msg-messages    syslog=off  [ deny count ]
process.max-msg-qbytes      syslog=off  [ deny bytes ]
process.max-sem-ops         syslog=off  [ deny count ]
process.max-sem-nsems       syslog=off  [ deny count ]
process.max-address-space   syslog=off  [ lowerable deny no-signal bytes ]
process.max-file-descriptor syslog=off  [ lowerable deny count ]
process.max-core-size       syslog=off  [ lowerable deny no-signal bytes ]
process.max-stack-size      syslog=off  [ lowerable deny no-signal bytes ]
.
.
.

Using ipcs

How to Use ipcs

Use the ipcs utility to display information about active interprocess communication (IPC) facilities. See the ipcs(1) man page for more information.

You can use ipcs with the -J option to see which project's limit an IPC object is allocated against.

# ipcs -J
    IPC status from <running system> as of Wed Mar 26 18:53:15 PDT 2003
T         ID      KEY        MODE       OWNER    GROUP    PROJECT
Message Queues:
Shared Memory:
m       3600      0       --rw-rw-rw-   uname    staff    x-files
m        201      0       --rw-rw-rw-   uname    staff    x-files
m       1802      0       --rw-rw-rw-   uname    staff    x-files
m        503      0       --rw-rw-rw-   uname    staff    x-files
m        304      0       --rw-rw-rw-   uname    staff    x-files
m        605      0       --rw-rw-rw-   uname    staff    x-files
m          6      0       --rw-rw-rw-   uname    staff    x-files
m        107      0       --rw-rw-rw-   uname    staff    x-files
Semaphores:
s          0      0       --rw-rw-rw-   uname    staff    x-files

Capacity Warnings

A global action on a resource control enables you to receive notice of any entity that is tripping over a resource control value that is set too low.

For example, assume you want to determine whether a web server possesses sufficient CPUs for its typical workload. You could analyze sar data for idle CPU time and load average. You could also examine extended accounting data to determine the number of simultaneous processes that are running for the web server process.

However, an easier approach is to place the web server in a task. You can then set a global action, using syslog, to notify you whenever a task exceeds a scheduled number of LWPs appropriate for the machine's capabilities.

See the sar(1) man page for more information.