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Dynamic System V Semaphore Tunables

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Overview

 

DynSysVSem, revision B.11.31.01

This is an optional Dynamic System V Semaphore Tunables product bundle, which contains a product, DynSysVSem, revision B.11.31.01, that allows the system administrator to change the system V semaphore tunable(s) value(s) dynamically without requiring a reboot of the system.

 

Without this product, system V semaphore tunables are static and any change in their values requires a reboot of the system. With the product, system V semaphore tunables are dynamic and any change in their values does not require a reboot (with a few exceptions).

 

DynSysVSem, revision B.11.31.02

This version of the bundle contains a product (DynsysVsem, revision B.11.31.02), which additionally provides virtualization support for HP-UX SRP A.03.00.

 

Features and Benefits

 

Dynamic System V Semaphore Tunables provides the following features and benefits:

 

  • Makes system V semaphore tunables easier to manage and reduces the need for scheduled reboots.
  • Allows increase and decrease in the value of semmni, semmns and semmsl tunables dynamically.
  • Allows increase in the value of semaem, semvmx tunables dynamically but requires a reboot for any decrease in their values.
  • Removes limitations on the number of semaphore undo operations done by a given process. It is unnecessary to adjust the semmnu and semume tunables when this product is installed and configured.
  • Internal locking is improved. It is unnecessary to adjust the sysv_hash_locks tunable value when this product is installed and configured.
  • Provides better system performance due to improved multi processor scaling and improved algorithms.
  • Additionally provides virtualization support for HP-UX SRP A.03.00.

Cautions

  • Before removing this product the tunable settings should be reviewed. For instance, with the product installed, the semmnu and semume tunables have no effect on boot-time kernel memory consumption. However, if they are set to high values and the DynSysVSem product bundle is removed, the system may fail to boot or perform as desired. Please refer to the man pages of system V semaphore tunables by installing the patch PHKL_37849. Check the HPE IT Resource Center for the latest information.
  • Care should be taken when increasing the value of semaem, semvmx tunables as only increase in the value of these tunables is dynamic and any subsequent decrease in the value would require a reboot of the system. Please refer to the man pages of semaem and semvmx by installing the patch PHKL_37849. Check the HPE IT Resource Center for the latest information.

Required / Optional patches

The revision B.11.31.02 of DynSysVSem product bundle contains only the product depot required for dynamic system V semaphore tunables functionality. Required and optional patches for dynamic system V semaphore tunables are listed in the table below. These patches are not contained in DynSysVSem product bundle.

Note: The DynSysVSem product bundle web depot file [DynSysVSem_*].depot contains the required patch PHKL_41891 along with the product bundle for installation.

HPE recommends installation of PHKL_37849 as the man page updates provide important additional information about behavior of the system V semaphore tunables when the DynSysVSem product bundle is installed. This patch is not included in the DynSysVSem product bundle and is not automatically installed.

Required/Optional Patches

Category

Patch Description

Product Name

Patch

Required

pm_usync cumulative patch

DynsysVsem

PHKL_41891

Optional

DynsysVsem man page patch

DynsysVsem

PHKL_37849

 

 
Additional product information
Product #: DynSysVSem
Version: B.11.31.02
Software specification: HP-UX 11.31 IA/PA(DynSysVSem_B.11.31.02_HP-UX_B.11.31_IA_PA.depot)
Installation
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