>Psychtoolbox>PsychPriority

priority=MachSetPriorityMex(policyFlavorString [,arg1] [,arg2] [,arg3] [,arg4])

OS X: ___________________________________________________________________

Set one of three priority flavors for the main MATLAB thread:
‘THREAD_STANDARD_POLICY’, ‘THREAD_TIME_CONSTRAINT_POLICY’,
‘THREAD_PRECEDENCE_POLICY’.

Each of the threed flavors has an associated set of parameters
following the flovor argument string in the first position:

MachSetPriorityMex(‘THREAD_STANDARD_POLICY’);
There are no parameters.

MachSetPriorityMex(‘THREAD_TIME_CONSTRAINT_POLICY’,
‘periodTicks’,’computationTicks’, ‘constraint’, ‘preemptible’);
See MachSetTimeConstrainPriority for an explanation of arguments. Note
that MachSetPriorityMex arguments “period”,”computation”, and
“constraint” are in units of bus tick rate which depends on you
particular model of computer, whereas MachSetTimeConstrainPriority
accepts arguments in units of seconds. Therefore it is better to use
MachSetTimeConstrainPriority than MachSetPriorityMex.

MachSetPriorityMex(‘THREAD_PRECEDENCE_POLICY’, ‘importance’);
Set the priority of the main MATLAB thread relative to other threads of
the MATLAB process. This is not useful.

Parameters for any priority flavor may be omitted and the single string
argument ‘default’ substituted in their place:
MachSetPriorityMex(‘THREAD_STANDARD_POLICY’, ‘default’);
MachSetPriorityMex(‘THREAD_TIME_CONSTRAINT_POLICY’, ‘default’);
MachSetPriorityMex(‘THREAD_PRECEDENCE_POLICY’, ‘default’);
Call MachGetPriorityMex with the ‘default’ flag argument set to discover
default values. The default values are provided by the the underlying
thread_policy_get() function.

There are three policy flavors but a thread may have only one of two
policy modes: THREAD_STANDARD_POLICY or THREAD_TIME_CONSTRAINT_POLICY.
These are mutually-exclusive modes; setting a thread to either one will
unset the other mode. The “importance” parameter associated with
THREAD_PRECEDENCE_POLICY is preserved after either THREAD_STANDARD_POLICY
or THREAD_TIME_CONSTRAINT_POLICY is set, however the
THREAD_PRECEDENCE_POLICY setting is ignored by the Mach task scheduler
while a thread is in THREAD_TIME_CONSTRAINT_POLICY mode. A thread is
governed by the THREAD_PRECEDENCE_POLICY “importance” parameter only
when in THREAD_STANDARD_POLICY mode.

MachSetPriorityMex calls the OS X Dawrin function thread_policy_set().
for more information on thread_policy_set() see:
Psychtoolbox3/Source/Common/MachPriorityMex/MachGetPriorityMex.c
Psychtoolbox3/Source/Common/MachPriorityMex/MachSetPriorityMex.c
http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming/scheduler/chapter_8_section_4.html
/usr/include/mach/thread_policy.h

OS 9: ___________________________________________________________________

MachSetPriorityMex does not exist in OS 9.

WINDOWS: ________________________________________________________________

MachSetPriorityMex does not exist in Windows.

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see also: Priority, Rush, MachGetPriorityMex, MachSetTimeConstraintPolicy