For RT-Semaphores used as mutexes
, if the BPIP had raised the caller's priority when it locked the semaphore, its priority is returned to its base priority specified in the MRT_setpattr() System Call.
number of nonzero Matrix number of rows/cols total average row col N row/col min max min max mutex09 65535 1114079 17.0 16 17 16 17 mutex12 263950 4031310 15.3 9 21 9 21 ncd07 62196 420036 6.8 2 7 2 7 ncd10 176851 1207051 6.8 2 7 2 7 gnatm06 79220 533120 6.7 3 9 4 7 gnatm07 130068 875896 6.7 3 9 4 7 tcomm16 13671 67381 4.9 2 5 2 5 tcomm20 17081 84211 4.9 2 5 2 5 twod08 66177 263425 4.0 2 4 2 4 twod10 263169 1050625 4.0 2 4 2 4 TABLE 5.2 Properties of the partitions and the induced block structures averaged over all matrices excluding mutex
In the Mutex
example, B = 14 implies no grouping; that is, the 14 automata are kept separate.
The explicit proposition layers can aid mutex propagation, allowing TPSys to compute more mutexes than Temporal GraphPlan (Garrido, Onaindia, and Barber 2001).
After computing I(a, b) = Pr(a [and] b) / Pr(a)P(b), having I(a, b) = 0 means that a and b are mutex, having I(a, b) = 1 means that a and b are independent, having 0 < I(a, b) < 1 means that a and b negatively interact, and having 1 < I(a, b) means that a and b positively interact.
If a process holds a mutex channel of type [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], then it has the capability to send/receive a value along the channel (the send operation is allowed only once), but it only has an obligation to send a value: it need not receive a value from the channel.
As another example, suppose [t.sub.x] is the time tag of a mutex channel x and [t.sub.y] is the time tag of another channel y, then
The following two invariants describe the bubble of mutual exclusion on entry to rmeld and rxmeld (lines 1 and 8 in Figure 4): First, the current process has exclusive use of the pointer variable referenced by q, so mutex
(the associated semaphore) is zero.
First, two action instances at level i are mutex
if either (1) the effect of one action is the negation of another action's effect (inconsistent effects), (2) one action deletes the precondition of another (interference), or (3) the actions have preconditions that are mutually exclusive at level i - 1 (competing needs).
A traditional approach to an assurance of the shared resources consistency is a usage of mutexes
Older modelers programmed their thread-safety after the fact by using mutexes
, severely limiting the speed at which the computer can utilize multiprocessor capabilities.
* crTRi[0:3][31:0] memorizes the events validated or inhibited by the wait nHSE instruction, one bit for each of the seven events (from right to left, the events generated by the timer, by the watchdog, by deadline 1 and deadline 2, by interrupts, mutexes
and synchronizing events, are validated (1) or inhibited (0)).