Installation guide

5.6.5.1 Symmetrical Multiprocessing
You do not have to add special configuration options for symmetrical
multiprocessing (SMP). The system determines at boot time whether it has
multiple CPUs and configures itself accordingly. The default for
multiprocessor systems is to configure SMP. For information on how to
override this default, see System Configuration and Tuning.
The following mandatory configuration file options have been added to
support SMP:
Option Definition Required
SER_COMPAT
Yes
UNIX_LOCKS
Yes
5.6.5.2 Real-Time Processing
You can enable real-time preemption on your system by defining the
RT_PREEMPT_OPT keyword. When this keyword is defined, the system
interrupts lower priority processes more often than normal in favor of
higher priority processes.
Defining this keyword might degrade the throughput performance of your
system because the system spends more time context-switching than it does
when you omit the RT_PREEMP_OPT keyword from the configuration file.
Other, required kernel options keywords that are related to real-time
processing are as follows:
• RT_PML
• RT_PREEMPT_OPT
• RT_SCHED
• RT_SCHED_RQ
• RT_SEM
• RT_TIMER
Do not remove these required options keywords from your configuration file.
5.6.5.3 Maximum Size of Switch Tables
To accommodate loadable subsystems, you might need to increase the
number of entries in the block and character switch tables. The following
example shows an error message from the config program that indicates
the need for more entries in the block and character switch tables:
5–50 Configuring the Kernel