Multi-threading: Difference between revisions

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Lower priority values give the thread higher priority. For userland apps, priorities between 0x18 and 0x3F are allowed. The priority of the app's main thread seems to be 0x30.

The thread scheduler is cooperative, therefore if a thread takes up all the CPU time (for example if it enters an endless loop), all the other threads that run on the same CPU core won't get a chance to run. The main way of yielding another thread is using an address arbiter.

The [[Glossary#appcore|appcore]] thread scheduler primarily uses a cooperative design, therefore if a thread takes up all the CPU time (for example if it enters an endless loop), all the other threads that run on the same CPU core won't get a chance to run. The main way of yielding another thread is using an address arbiter. In certain cases, execution of the current task may be preempted regardless, for instance when a thread was waiting on svcSendSyncRequest to return.

0xFFFF8000 is a handle alias for the currently active thread.

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* KClientPort: Wakes if max sessions not reached (free session available)

* KClientSession: Always false?

* KDebug: ~~???~~

* KDebug: Waits until a debug event is signaled (the user should then use svcGetProcessDebugEvent to get the debug event info)

* KDmaObject: ???

* KEvent: Waits until the event is signaled

* KInterruptEvent: ???

* KMutex: Acquires a lock on the mutex (blocks until this succeeds)

* KProcess: Waits until the process exits

* KProcess: Waits until the process exits/is terminated

* KSemaphore: This consumes a value from the semaphore count, if possible, otherwise continues to wait

* KServerPort: Waits for a new client connection, upon which svcAcceptSession is ready to be called

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=== ReleaseMutex ===

~~== Critical Section (light-weight mutex) ==~~

~~Similar to a mutex, but faster and no priority inheritance. Therefore problems such as priority inversion may occur.~~

~~=== CriticalSection::Initialize ===~~

~~Creates an object~~

~~=== CriticalSection::Enter ===~~

~~Locks out threads from accessing a critical section.~~

~~=== CriticalSection::Leave ===~~

~~Unlocks and allows for access to a critical section.~~

== Semaphore ==

~~== Light Semaphore ==~~

== Event ==

~~== Light Event ==~~

== Address Arbiters ==

@@ Line 98: / Line 98: @@
 Lower priority values give the thread higher priority. For userland apps, priorities between 0x18 and 0x3F are allowed. The priority of the app's main thread seems to be 0x30.
-The thread scheduler is cooperative, therefore if a thread takes up all the CPU time (for example if it enters an endless loop), all the other threads that run on the same CPU core won't get a chance to run. The main way of yielding another thread is using an address arbiter.
+The [[Glossary#appcore|appcore]] thread scheduler primarily uses a cooperative design, therefore if a thread takes up all the CPU time (for example if it enters an endless loop), all the other threads that run on the same CPU core won't get a chance to run. The main way of yielding another thread is using an address arbiter. In certain cases, execution of the current task may be preempted regardless, for instance when a thread was waiting on svcSendSyncRequest to return.
 xFFFF8000 is a handle alias for the currently active thread.
@@ Line 265: / Line 265: @@
 * KClientPort: Wakes if max sessions not reached (free session available)
 * KClientSession: Always false?
-* KDebug: ???
+* KDebug: Waits until a debug event is signaled (the user should then use svcGetProcessDebugEvent to get the debug event info)
 * KDmaObject: ???
 * KEvent: Waits until the event is signaled
-* KInterruptEvent: ???
 * KMutex: Acquires a lock on the mutex (blocks until this succeeds)
-* KProcess: Waits until the process exits
+* KProcess: Waits until the process exits/is terminated
 * KSemaphore: This consumes a value from the semaphore count, if possible, otherwise continues to wait
 * KServerPort: Waits for a new client connection, upon which svcAcceptSession is ready to be called
@@ Line 288: / Line 287: @@
 === ReleaseMutex ===
-== Critical Section (light-weight mutex) ==
-Similar to a mutex, but faster and no priority inheritance. Therefore problems such as priority inversion may occur.
-=== CriticalSection::Initialize ===
-Creates an object
-=== CriticalSection::Enter ===
-Locks out threads from accessing a critical section.
-=== CriticalSection::Leave ===
-Unlocks and allows for access to a critical section.
 == Semaphore ==
-== Light Semaphore ==
 == Event ==
-== Light Event ==
 == Address Arbiters ==