HP-UX 11i June 2003 Release Notes

Process, Threads, Memory, and Kernel Parameters
Changes to mpctl() System Call
Chapter 10
221
Changes to mpctl() System Call
new at 11i
original release
Some extensions have made to the mpctl() system call interface to pre-enable processor
set functionality in the HP-UX 11i release.
The mpctl() interface provides command requests to query system information, such as
the total number of processors and locality domains in the system, and the IDs of all
processors and locality domains. When processor set functionality is implemented in
HP-UX, these command requests will return information about the processor set of the
calling thread, and not the entire system.
A new set of mpctl() command options query for system-wide topology information,
regardless of which processor set contains those resources. The following seven new
command requests are provided in HP-UX 11i:
The new command requests are mapped to their current equivalent requests in the 11i
release, so applications in the 11i release are not affected.
When the processor set functionality becomes available, applications that rely on
mpctl() to return system level information will need to be changed to use new command
requests. For these applications we recommend using the new commands in the 11i
release to avoid any issues when processor sets are available.
All applications that use mpctl() to query the available processors and locality domains
to scale and bind for optimal performance will not require any changes when the
processor set functionality is made available. The mpctl()’s existing commands will
return information about what processors are available for binding.
When processor set functionality becomes available, if the system is not partitioned into
more than one processor sets, no applications using the mpctl() interface with current
command requests will be affected.
Table 10-1 New mpctl() Command Requests
New Request Its Equivalent in 11i
MPC_GETNUMSPUS_SYS MPC_GETNUMSPUS
MPC_GETFIRSTSPU_SYS MPC_GETFIRSTSPU
MPC_GETNEXTSPU_SYS MPC_GETNEXTSPU
MPC_GETNUMLDOMS_SYS MPC_GETNUMLDOMS
MPC_GETFIRSTLDOM_SYS MPC_GETFIRSTLDOM
MPC_GETNEXTLDOM_SYS MPC_GETNEXTLDOM
MPC_LDOMSPUS_SYS MPC_LDOMSPUS