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A spurious interrupt may result in system deadlock or other undefined operation if the ISR does not account for the possibility of such an interrupt occurring. As spurious interrupts are mostly a problem with wired-OR interrupt circuits, good programming practice in such systems is for the ISR to check all interrupt sources for activity and ...
When disabling interrupts is used to prevent priority inversion, there are only two priorities: preemptible, and interrupts disabled. With no third priority, inversion is impossible. Since there's only one piece of lock data (the interrupt-enable bit), misordering locking is impossible, and so deadlocks cannot occur.
Does linear programming admit a strongly polynomial-time algorithm? (This is problem #9 in Smale's list of problems.) How many queries are required for envy-free cake-cutting? What is the algorithmic complexity of the minimum spanning tree problem? Equivalently, what is the decision tree complexity of the MST problem?
The problem of spurious wakeup can be exacerbated on multiprocessor systems. When several threads are waiting on a single condition variable, the system may decide to wake all threads up when it's signaled.
In the C Standard Library, signal processing defines how a program handles various signals while it executes. A signal can report some exceptional behavior within the program (such as division by zero), or a signal can report some asynchronous event outside the program (such as someone striking an interactive attention key on a keyboard).
The interrupt priority level (IPL) is a part of the current system interrupt state, which indicates the interrupt requests that will currently be accepted. The IPL may be indicated in hardware by the registers in a programmable interrupt controller , or in software by a bitmask or integer value and source code of threads.
For example, pressing a key on a computer keyboard, [1] or moving the mouse, triggers interrupts that call interrupt handlers which read the key, or the mouse's position, and copy the associated information into the computer's memory. [2] An interrupt handler is a low-level counterpart of event handlers.
an invalid instruction that causes a deliberate program interrupt (that is then intercepted/handled by the debugger) This technique may be more difficult to implement in multitasking systems using shared program storage (the interrupt may occur on a different thread, requiring resurrection of the original instruction for that thread).