ACE_Sched_Params Class Reference

Container for scheduling-related parameters. More...

#include <Sched_Params.h>

Collaboration diagram for ACE_Sched_Params:

Collaboration graph
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List of all members.

Public Types

typedef int Policy

Public Member Functions

 ACE_Sched_Params (const Policy policy, const ACE_Sched_Priority priority, const int scope=ACE_SCOPE_THREAD, const ACE_Time_Value &quantum=ACE_Time_Value::zero)
 Constructor.
 ~ACE_Sched_Params (void)
 Termination.
Policy policy (void) const
void policy (const Policy)
ACE_Sched_Priority priority (void) const
void priority (const ACE_Sched_Priority)
int scope (void) const
void scope (const int)
const ACE_Time_Valuequantum (void) const
void quantum (const ACE_Time_Value &)

Static Public Member Functions

static int priority_min (const Policy, const int scope=ACE_SCOPE_THREAD)
static int priority_max (const Policy, const int scope=ACE_SCOPE_THREAD)
static int next_priority (const Policy, const int priority, const int scope=ACE_SCOPE_THREAD)
static int previous_priority (const Policy, const int priority, const int scope=ACE_SCOPE_THREAD)

Private Attributes

Policy policy_
 Scheduling policy.
ACE_Sched_Priority priority_
int scope_
ACE_Time_Value quantum_

Detailed Description

Container for scheduling-related parameters.

ACE_Sched_Params are passed via <ACE_OS::sched_params> to the OS to specify scheduling parameters. These parameters include scheduling policy, such as FIFO (ACE_SCHED_FIFO), round-robin (ACE_SCHED_RR), or an implementation-defined "OTHER" (ACE_SCHED_OTHER), to which many systems default; priority; and a time-slice quantum for round-robin scheduling. A "scope" parameter specifies whether the ACE_Sched_Params applies to the current process, current lightweight process (LWP) (on Solaris), or current thread. Please see the "NOTE" below about not all combinations of parameters being legal on a particular platform. For the case of thread priorities, it is intended that <ACE_OS::sched_params> usually be called from <main> before any threads have been spawned. If spawned threads inherit their parent's priority (I think that's the default behavior for all of our platforms), then this sets the default base priority. Individual thread priorities can be adjusted as usual using <ACE_OS::thr_prio> or via the ACE_Thread interface. See the parameter descriptions in the private: section below. NOTE: this class does not do any checking of parameters. It is just a container class. If it is constructed with values that are not supported on a platform, the call to <ACE_OS::sched_params> will fail by returning -1 with EINVAL (available through <ACE_OS::last_error>).


Member Typedef Documentation

typedef int ACE_Sched_Params::Policy
 


Constructor & Destructor Documentation

ACE_INLINE ACE_Sched_Params::ACE_Sched_Params const Policy  policy,
const ACE_Sched_Priority  priority,
const int  scope = ACE_SCOPE_THREAD,
const ACE_Time_Value quantum = ACE_Time_Value::zero
 

Constructor.

ACE_INLINE ACE_Sched_Params::~ACE_Sched_Params void   ) 
 

Termination.


Member Function Documentation

int ACE_Sched_Params::next_priority const   Policy,
const int  priority,
const int  scope = ACE_SCOPE_THREAD
[static]
 

The next higher priority. "Higher" refers to scheduling priority, not to the priority value itself. (On some platforms, higher scheduling priority is indicated by a lower priority value.) If "priority" is already the highest priority (for the specified policy), then it is returned.

ACE_INLINE void ACE_Sched_Params::policy const   Policy  ) 
 

ACE_INLINE ACE_Sched_Params::Policy ACE_Sched_Params::policy void   )  const
 

int ACE_Sched_Params::previous_priority const   Policy,
const int  priority,
const int  scope = ACE_SCOPE_THREAD
[static]
 

The previous, lower priority. "Lower" refers to scheduling priority, not to the priority value itself. (On some platforms, lower scheduling priority is indicated by a higher priority value.) If "priority" is already the lowest priority (for the specified policy), then it is returned.

ACE_INLINE void ACE_Sched_Params::priority const   ACE_Sched_Priority  ) 
 

ACE_INLINE ACE_Sched_Priority ACE_Sched_Params::priority void   )  const
 

int ACE_Sched_Params::priority_max const   Policy,
const int  scope = ACE_SCOPE_THREAD
[static]
 

int ACE_Sched_Params::priority_min const   Policy,
const int  scope = ACE_SCOPE_THREAD
[static]
 

ACE_INLINE void ACE_Sched_Params::quantum const ACE_Time_Value  ) 
 

ACE_INLINE const ACE_Time_Value & ACE_Sched_Params::quantum void   )  const
 

ACE_INLINE void ACE_Sched_Params::scope const   int  ) 
 

ACE_INLINE int ACE_Sched_Params::scope void   )  const
 


Member Data Documentation

Policy ACE_Sched_Params::policy_ [private]
 

Scheduling policy.

ACE_Sched_Priority ACE_Sched_Params::priority_ [private]
 

Default <priority_>: for setting the priority for the process, LWP, or thread, as indicated by the scope_ parameter.

ACE_Time_Value ACE_Sched_Params::quantum_ [private]
 

The <quantum_> is for time slicing. An ACE_Time_Value of 0 has special significance: it means time-slicing is disabled; with that, a thread that is running on a CPU will continue to run until it blocks or is preempted. Currently ignored if the OS doesn't directly support time slicing, such as on VxWorks, or setting the quantum (can that be done on Win32?).

int ACE_Sched_Params::scope_ [private]
 

<scope_> must be one of the following: ACE_SCOPE_PROCESS: sets the scheduling policy for the process, and the process priority. On some platforms, such as Win32, the scheduling policy can _only_ be set at process scope. ACE_SCOPE_LWP: lightweight process scope, only used with Solaris threads. ACE_SCOPE_THREAD: sets the scheduling policy for the thread, if the OS supports it, such as with Posix threads, and the thread priority. NOTE: I don't think that these are the same as POSIX contention scope. POSIX users who are interested in, and understand, contention scope will have to set it by using system calls outside of ACE.


The documentation for this class was generated from the following files:
Generated on Wed Nov 23 15:50:18 2005 for ACE by  doxygen 1.4.5