HP-UX 11i June 2001 Release Notes

Process, Threads, Memory, and Kernel Parameters
Dynamic Tunables (new at 11i original release)
Chapter 8 171
Dynamic Tunables (new at 11i original
release)
A new facility has been added which will allow the retrieving of all
tunable values and the setting of a limited number of tunables. If a
tunable is dynamic, a change will take place immediately, without the
need to reboot the system. Such changes will persist across reboots.
Three parts of the system have been changed to allow retrieving and
setting of dynamic tunable values:
• System Administration Manager (SAM). For details, see “Changes to
System Administration Manager (SAM)(updated for June 2001)” on
page 142 in this document and the SAM Online Help Facility.
• kmtune. This command has been enhanced to allow the changing of
dynamic tunables. See the kmtune (1M) manpage for further details.
• Three new system calls have been added: gettune (2), settune (2) and
tuneinfo (2). See the manpage for each of these new system calls for
their function and use.
Currently, the following tunables are dynamic:
• maxuprc- Maximum number of user processes
• msgmax- Message maximum size in bytes
• msgmnb - Maximum number of bytes on a message queue
• shmmax - Maximum shared memory segment size in bytes
• shmseg - Shared memory segments per process
• maxtsiz- Maximum text segment size in bytes for 32 bit programs
• maxtsiz_64bit- Maximum text segment size in bytes for 64 bit
programs
• maxfiles_lim - Hard file limit per process
• core_addshmem_read -Include readable shared memory in process
core dump
• core_addshmem_write -Include writable shared memory in process
core dump
For more information, see the white paper Dynamically Tunable Kernel
Parameters in HP-UX 11i at http://docs.hp.com.