priority inversion การใช้

• Priority inversion can also reduce the perceived performance of the system.
• The mission was jeopardised by a computer resets caused by priority inversion.
• The scheduler was designed to avoid priority inversion.
• This condition is called a priority inversion.
• However, there are also many situations in which priority inversion can cause serious problems.
• There are several well-known problems with semaphore based designs such as priority inversion and deadlocks.
• This hazard of deadline interchange is analogous to priority inversion when using fixed priority pre-emptive scheduling.
• For example, certain interactions between locks can lead to error conditions such as deadlock, livelock, and priority inversion.
• Issues such as deadlock and priority inversion can be very difficult to avoid, and require coordination at many levels of the kernel.
• Priority inversion can still be an issue, but high-priority transactions can abort conflicting lower priority transactions that have not already committed.
• For ensuring this under fault conditions the system designer has to define the behaviour under these conditions ( error frames and avoidance of priority inversion ).
• In many practical applications, resources are shared and the unmodified "'RMS "'will be subject to priority inversion and deadlock hazards.
• In priority inversion a high priority task waits because a low priority task has a semaphore, but the lower priority task is not given CPU time to finish its work.
• In some cases, priority inversion can occur without causing immediate harm the delayed execution of the high priority task goes unnoticed, and eventually the low priority task releases the shared resource.
• Because priority inversion results in the execution of a lower priority task blocking the high priority task, it can lead to reduced system responsiveness, or even the violation of response time guarantees.
• For example, classic starvation, in which a process never gets sufficient resources to run to completion; priority inversion, in which a higher priority thread waits for a lower-priority thread; and high latency, in which response to interrupts is not prompt.
• Among other things, the use of serializing tokens prevents many of the situations that could result in deadlocks and priority inversions when using mutexes, as well as greatly simplifying the design and implementation of a many-step procedure that would require a resource to be shared among multiple threads.
• It's the primary reason why a runaway Linux or OSX system is easily fixed through ssh-the shell's fractional memory pressure and limited dependence on other processes makes it easy to use them to get the attention and kill the runaway processes . ( Unfortunately, this is hard to reference-priority inversion describes part of the problem, but not why a runaway process not directly involved in the system overload, can still manage to grind the system to a halt ) . talk ) 20 : 14, 26 September 2012 ( UTC)