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Rate-monotonic scheduling

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1624:(ISRs), whether they have a hard real-time deadline or not should be included in RMS analysis to determine schedulability in cases where ISRs have priorities above all scheduler-controlled tasks. An ISR may already be appropriately prioritized under RMS rules if its processing period is shorter than that of the shortest, non-ISR process. However, an ISR with a period/deadline longer than any non-ISR process period with a critical deadline results in a violation of RMS and prevents the use of the calculated bounds for determining schedulability of a task set. 1632:
One method for mitigating a mis-prioritized ISR is to adjust the analysis by reducing the ISR's period to be equal to that of the shortest period, if possible. Imposing this shorter period results in prioritization that conforms to RMS, but also results in a higher utilization factor for the ISR and
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Priority inheritance algorithms can be characterized by two parameters. First, is the inheritance lazy (only when essential) or immediate (boost priority before there is a conflict). Second is the inheritance optimistic (boost a minimum amount) or pessimistic (boost by more than the minimum amount):
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Another method for mitigating a mis-prioritized ISR is to use the ISR to only set a new semaphore/mutex while moving the time-intensive processing to a new process that has been appropriately prioritized using RMS and will block on the new semaphore/mutex. When determining schedulability, a margin
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It has been shown that a randomly generated periodic task system will usually meet all deadlines when the utilization is 88% or less, however this fact depends on knowing the exact task statistics (periods, deadlines) which cannot be guaranteed for all task sets, and in some cases the authors found
1967:. This utilization factor would be used when adding up the total utilization factor for the task set and comparing to the upper bound to prove schedulability. It should be emphasized that adjusting the period of the ISR is for analysis only and that the true period of the ISR remains unchanged. 1543:
to each semaphore, which is the priority of the highest job that will ever access that semaphore. A job cannot preempt a lower priority critical section if its priority is lower than the ceiling priority for that section. This method prevents deadlocks and bounds the blocking time to at most the
1148:. It is acknowledged by Liu and Layland that it is not always feasible to have a harmonic task set and that in practice other mitigation measures, such as buffering for tasks with soft-time deadlines or using a dynamic priority assignment approach may be used instead to allow for a higher bound. 115:
algorithm is also optimal with equal periods and deadlines, in fact in this case the algorithms are identical; in addition, deadline monotonic scheduling is optimal when deadlines are less than periods. For the task model in which deadlines can be greater than periods, Audsley's algorithm endowed
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promotes the priority of the task that holds the resource to the priority of the task that requests that resource at the time the request is made. Upon release of the resource, the original priority level before the promotion is restored. This method does not prevent deadlocks and suffers from
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In practice there is no mathematical difference (in terms of the Liu-Layland system utilization bound) between the lazy and immediate algorithms, and the immediate algorithms are more efficient to implement, and so they are the ones used by most practical systems.
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The actual reason for the Mars Pathfinder Bug, by those who actually dealt with it, rather than someone whose company and therefore stock value depended upon the description of the problem, or someone who heard someone talking about the
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schedulers fail to meet the scheduling needs otherwise. Rate monotonic scheduling looks at a run modeling of all threads in the system and determines how much time is needed to meet the guarantees for the set of threads in question.
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therefore for the total utilization factor, which may still be below the allowable bound and therefore schedulability can be proven. As an example, consider a hardware ISR that has a computation time,
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and have deterministic guarantees with regard to response times. Rate monotonic analysis is used in conjunction with those systems to provide scheduling guarantees for a particular application.
1861: 1428: 35:(RTOS) with a static-priority scheduling class. The static priorities are assigned according to the cycle duration of the job, so a shorter cycle duration results in a higher job priority. 630: 683: 2582: 1913: 910: 1965: 3273: 3045: 1780: 3447: 4096: 3212: 3025: 2562: 2268: 1544:
length of one lower priority critical section. This method can be suboptimal, in that it can cause unnecessary blocking. The priority ceiling protocol is available in the
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In the instance where for each task, its period is an exact multiple of every other task that has a shorter period, the task set can be thought of as being composed of
945: 1515:. That is, if a high priority task accesses multiple shared resources in sequence, it may have to wait (block) on a lower priority task for each of the resources. The 488: 146: 1730: 1032: 1003: 974: 864: 835: 546: 517: 4063: 2834: 2371: 2149: 111:
under the given assumptions, meaning that if any static-priority scheduling algorithm can meet all the deadlines, then the rate-monotonic algorithm can too. The
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or avoid the sharing of a mutex/semaphore across threads with different priorities. This is so that resource conflicts cannot result in the first place.
3275:, tasks 2 and 3 can be considered a harmonic task subset. Task 1 forms its own harmonic task subset. Therefore, the number of harmonic task subsets, 706: 2344:
Under RMS, P2 has the highest release rate (i.e. the shortest release period) and so would have the highest priority, followed by P3 and finally P1.
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Under RMS, P2 has the highest release rate (i.e. the shortest release period) and so would have the highest priority, followed by P1 and finally P3.
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of 1 millisecond, then the ISR would have a higher priority, but a lower rate, which violates RMS. For the purposes of proving schedulability, set
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is the CPU utilization for each task. It is the tightest upper bound that can be found using only the individual task utilization factors.
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of CPU utilization due to ISR activity should be subtracted from the least upper bound. ISRs with negligible utilization may be ignored.
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Lehoczky, J.; Sha, L.; Ding, Y. (1989), "The rate monotonic scheduling algorithm: exact characterization and average case behavior",
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Under RMS, P2 has the highest rate (i.e. the shortest period) and so would have the highest priority, followed by P3 and finally P1.
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reset bug" which was fixed on Mars by changing the creation flags for the semaphore so as to enable the priority inheritance.
2842: 2379: 2157: 447:, is less than 70%. The other 30% of the CPU can be dedicated to lower-priority, non-real-time tasks. For smaller values of 4035: 1519: 3841:
Sha, L.; Rajkumar, R.; Lehoczky, J. P. (1990), "Priority inheritance protocols: an approach to real-time synchronization",
4258: 4146: 4086: 4049: 3458: 112: 4284: 2270:, and because being below the Least Upper Bound is a sufficient condition, the system is guaranteed to be schedulable. 4126: 3469: 1458: 1785: 1367: 1361:
The hyperbolic bound is a tighter sufficient condition for schedulability than the one presented by Liu and Layland:
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and recalculate the utilization factor for the ISR (which also raises the total utilization factor). In this case,
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Leung, J. Y.; Whitehead, J. (1982), "On the complexity of fixed-priority scheduling of periodic, real-time tasks",
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Static priorities (the task with the highest static priority that is runnable immediately preempts all other tasks)
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Enrico Bini; Giorgio C. Buttazzo; Giuseppe M. Buttazzo (2003), "Rate Monotonic Analysis: the Hyperbolic Bound",
2719:{\displaystyle \prod _{i=1}^{n}(U_{i}+1)=({\frac {3}{16}}+1)*({\frac {2}{5}}+1)*({\frac {2}{10}}+1)=1.995\leq 2} 4141: 3901: 641: 140:
utilization is below a specific bound (depending on the number of tasks). The schedulability test for RMS is:
4166: 137: 63: 3176:{\displaystyle \prod _{i=1}^{n}(U_{i}+1)=({\frac {7}{32}}+1)*({\frac {2}{5}}+1)*({\frac {2}{10}}+1)=2.0475} 1866: 4156: 4072: 3769: 3526: 3485: 869: 91: 39: 1918: 4111: 4101: 3466:, a time and space partitioned real-time operating system containing a working Rate Monotonic Scheduler. 3229: 808:
Liu and Layland noted that this bound may be relaxed to the maximum possible value of 1.0, if for tasks
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periodic tasks with unique periods, a feasible schedule that will always meet deadlines exists if the
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It is a mathematical model that contains a calculated simulation of periods in a closed system, where
4207: 4181: 3495: 3189: 1462: 3517:; Layland, J. (1973), "Scheduling algorithms for multiprogramming in a hard real-time environment", 548:
should represent the worst-case deadline (i.e. shortest period) in which all processing must occur.
3774: 3531: 1005:, which is to say that all tasks have a period that is not just a multiple of the shortest period, 2991: 2528: 2234: 416: 4253: 4131: 4006: 3787: 3703: 3662: 3568: 3544: 1454: 278:{\displaystyle U=\sum _{i=1}^{n}{U_{i}}=\sum _{i=1}^{n}{\frac {C_{i}}{T_{i}}}\leq n({2}^{1/n}-1)} 1034:, but instead that any task's period is a multiple of all shorter periods. This is known as an 50:
A simple version of rate-monotonic analysis assumes that threads have the following properties:
1671: 1636: 1315: 1283: 915: 4176: 4161: 3940: 3693: 3652: 3620: 461: 59: 1706: 1008: 979: 950: 840: 811: 522: 493: 3998: 3975: 3850: 3779: 3738: 3730: 3685: 3644: 3597: 3536: 20: 1312:, which makes this generalization equivalent to Liu and Layland's least upper bound. When 4116: 3575: 3514: 3490: 3482:, an open source real-time operating system containing a working Rate Monotonic Scheduler. 1609: 1523: 557: 2818: 2355: 2133: 86:
Context switch times and other thread operations are free and have no impact on the model
403:{\displaystyle \lim _{n\rightarrow \infty }n({\sqrt{2}}-1)=\ln 2\approx 0.693147\ldots } 4227: 4222: 4217: 3757: 1041: 116:
with an exact schedulability test for this model finds an optimal priority assignment.
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Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications
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Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications
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Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications
3666: 3413:{\displaystyle {U_{lub,harmonic}}=K(2^{\frac {1}{K}}-1)=2(2^{\frac {1}{2}}-1)=0.828} 4237: 3989:
Sha, Lui; Goodenough, John B. (April 1990), "Real-Time Scheduling Theory and Ada",
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family of primitives which nest the locking of device interrupts (FreeBSD 5.x/6.x),
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processes, under which we can conclude that the task set is schedulable, remains:
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processes, under which we can conclude that the task set is schedulable, remains:
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that the utilization reached the least upper bound presented by Liu and Layland.
790:{\displaystyle \rho _{i}={\lambda _{i} \over \mu _{i}}={C_{i} \over T_{i}}=U_{i}} 2815:
Using the Liu and Layland bound, as in Example 1, the sufficient condition for
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Using the Liu and Layland bound, as in Example 1, the sufficient condition for
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Joseph, M.; Pandya, P. (1986), "Finding response times in real-time systems",
1703:, of 4 milliseconds. If the shortest scheduler-controlled task has a period, 83:
conventions (tasks with shorter periods/deadlines are given higher priorities)
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T.-W. Kuo; A.K. Mok (1991). "Load adjustment in adaptive real-time systems".
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is close to this estimate, the calculated utilization bound should be used.
3783: 3760:; Redell, D. D. (1980), "Experience with processes and monitors in Mesa", 3540: 2151:
processes, under which we can conclude that the system is schedulable is:
1266:{\displaystyle U=\sum _{i=1}^{n}{\frac {C_{i}}{T_{i}}}\leq K({2}^{1/K}-1)} 3953: 323: 3743: 2977:{\displaystyle U={\frac {7}{32}}+{\frac {2}{5}}+{\frac {2}{10}}=0.81875} 1449:
In many practical applications, resources are shared and the unmodified
4041: 2514:{\displaystyle U={\frac {3}{16}}+{\frac {2}{5}}+{\frac {2}{10}}=0.7875} 1545: 3854: 3423:
Using the total utilization factor calculated above (0.81875), since
2119:{\displaystyle U={\frac {1}{8}}+{\frac {2}{5}}+{\frac {2}{10}}=0.725} 1608:
An example of usage of basic priority inheritance is related to the "
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should represent the worst-case (i.e. longest) computation time and
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is that RMS can meet all of the deadlines if total CPU utilization,
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hazards. In practice, this is solved by disabling preemption or by
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is the release period (with deadline one period later) for process
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to be guaranteed to be schedulable by the Liu and Layland bound.
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to be guaranteed to be schedulable by the Liu and Layland bound.
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enhances the basic priority inheritance protocol by assigning a
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primitives that lock CPU interrupts in a real-time kernel, e.g.
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priority ceiling protocol, basic priority inheritance protocol
3641:[1991] Proceedings Twelfth Real-Time Systems Symposium 3569:
http://oreilly.com/catalog/linuxkernel/chapter/ch10.html#85347
1344:, the upper bound becomes 1.0, representing full utilization. 322:
for two processes. When the number of processes tends towards
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What really happened on Mars Rover Pathfinder by Mike Jones
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be guaranteed to be schedulable by the Hyperbolic bound.
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is the number of processes to be scheduled. For example,
2906:{\displaystyle {U_{lub}}=3(2^{\frac {1}{3}}-1)=0.77976} 2443:{\displaystyle {U_{lub}}=3(2^{\frac {1}{3}}-1)=0.77976} 2221:{\displaystyle {U_{lub}}=3(2^{\frac {1}{3}}-1)=0.77976} 54:
No resource sharing (processes do not share resources,
582:. These two parameters are often specified as rates: 3872:(Third ed.), New York, NY: Springer, p. 212 3809:(Third ed.), New York, NY: Springer, p. 225 3429: 3292: 3232: 3192: 3048: 2994: 2925: 2845: 2821: 2585: 2531: 2462: 2382: 2358: 2237: 2160: 2136: 2067: 1921: 1869: 1788: 1738: 1709: 1674: 1639: 1370: 1318: 1286: 1173: 1044: 1011: 982: 953: 918: 872: 843: 814: 709: 644: 591: 525: 496: 464: 419: 335: 149: 73:
Deterministic deadlines are exactly equal to periods
4246: 4200: 4079: 3898:"Mars Pathfinder Reset Bug - Anthology of Interest" 3619:(4th ed.), Addison-Wesley, pp. 391, 397, 3441: 3412: 3267: 3206: 3175: 3019: 2976: 2905: 2828: 2718: 2556: 2513: 2442: 2365: 2262: 2220: 2143: 2118: 1959: 1907: 1855: 1774: 1724: 1695: 1660: 1422: 1336: 1304: 1265: 1156:Kuo and Mok showed that for a task set made up of 1140: 1026: 997: 968: 939: 904: 858: 829: 789: 677: 624: 540: 511: 482: 435: 402: 277: 337: 3039:Using the tighter Hyperbolic bound as follows: 2576:Using the tighter Hyperbolic bound as follows: 1856:{\displaystyle {U_{isr}}{=}{C_{isr}}/{T_{isr}}} 1423:{\displaystyle \prod _{i=1}^{n}(U_{i}+1)\leq 2} 1280:harmonic task subsets of size 1 and therefore 4057: 31:) is a priority assignment algorithm used in 8: 3449:the system is determined to be schedulable. 625:{\displaystyle \lambda _{i}={1 \over T_{i}}} 79:Static priorities assigned according to the 3937:Real-Time Systems and Programming Languages 3617:Real-Time Systems and Programming Languages 1530:includes an implementation of this formula. 4064: 4050: 4042: 129: 107:The rate-monotonic priority assignment is 3979: 3773: 3742: 3530: 3428: 3384: 3351: 3298: 3293: 3291: 3257: 3252: 3248: 3238: 3233: 3231: 3196: 3191: 3148: 3123: 3098: 3077: 3064: 3053: 3047: 3005: 2993: 2958: 2945: 2932: 2924: 2877: 2851: 2846: 2844: 2825: 2820: 2685: 2660: 2635: 2614: 2601: 2590: 2584: 2542: 2530: 2495: 2482: 2469: 2461: 2414: 2388: 2383: 2381: 2362: 2357: 2248: 2236: 2192: 2166: 2161: 2159: 2140: 2135: 2100: 2087: 2074: 2066: 1949: 1938: 1933: 1922: 1920: 1897: 1886: 1881: 1870: 1868: 1840: 1835: 1830: 1817: 1812: 1807: 1794: 1789: 1787: 1765: 1760: 1744: 1739: 1737: 1715: 1710: 1708: 1680: 1675: 1673: 1645: 1640: 1638: 1399: 1386: 1375: 1369: 1329: 1324: 1319: 1317: 1297: 1292: 1287: 1285: 1244: 1240: 1235: 1217: 1207: 1201: 1195: 1184: 1172: 1098: 1093: 1083: 1078: 1068: 1063: 1053: 1048: 1043: 1017: 1012: 1010: 988: 983: 981: 959: 954: 952: 917: 895: 890: 885: 878: 873: 871: 849: 844: 842: 820: 815: 813: 781: 766: 756: 750: 739: 729: 723: 714: 708: 667: 658: 649: 643: 614: 605: 596: 590: 531: 526: 524: 502: 497: 495: 470: 465: 463: 428: 420: 418: 363: 358: 340: 334: 256: 252: 247: 229: 219: 213: 207: 196: 182: 177: 171: 160: 148: 4097:Earliest eligible virtual deadline first 4032:from The Risks Digest, Vol. 19, Issue 49 2740: 2277: 1983: 1559: 678:{\displaystyle \mu _{i}={1 \over C_{i}}} 16:Scheduling technique in computer science 3960:, Upper Saddle River, NJ: Prentice Hall 3506: 1164:), the least upper bound test becomes: 693:The utilization for each task, denoted 4172:Statistical time-division multiplexing 1548:real-time kernel. It is also known as 38:These operating systems are generally 3935:Alan Burns and Andy Wellings (2009), 3615:Alan Burns and Andy Wellings (2009), 1908:{\displaystyle {0.5ms}/{4ms}{=}0.125} 326:, this expression will tend towards: 7: 905:{\displaystyle {T_{m}}{>}{T_{i}}} 299:is the computation time for process 1960:{\displaystyle {0.5ms}/{1ms}{=}0.5} 1508:basic priority inheritance protocol 3884:"Mike Jones at Microsoft Research" 3475:Earliest deadline first scheduling 3268:{\displaystyle {T_{3}}={2{T_{2}}}} 1668:of 500 microseconds and a period, 1550:Highest Locker's Priority Protocol 804:Upper bound for harmonic task sets 347: 62:resource, a queue, or any kind of 14: 4122:Generalized foreground-background 3562:Bovet, Daniel P.; Cesati, Marco, 1775:{\displaystyle {T_{isr}}={T_{1}}} 1465:. Alternative methods are to use 1152:Generalization to harmonic chains 1038:. An example of this would be: 413:Therefore, a rough estimate when 3939:(4th ed.), Addison-Wesley, 3682:IEEE Real-Time Systems Symposium 3442:{\displaystyle 0.81875<0.828} 2916:The total utilization will be: 2453:The total utilization will be: 1160:harmonic task subsets (known as 4280:Processor scheduling algorithms 3207:{\displaystyle 2.0{<}2.0475} 1628:Mitigating mis-prioritized ISRs 552:Relationship to queueing theory 3843:IEEE Transactions on Computers 3723:IEEE Transactions on Computers 3564:Understanding the Linux Kernel 3401: 3377: 3368: 3344: 3164: 3145: 3139: 3120: 3114: 3095: 3089: 3070: 2894: 2870: 2729:it is found that the task set 2701: 2682: 2676: 2657: 2651: 2632: 2626: 2607: 2431: 2407: 2209: 2185: 1411: 1392: 1260: 1231: 1135: 1111: 1105: 1045: 376: 355: 344: 272: 243: 1: 3459:Deadline-monotonic scheduling 2130:The sufficient condition for 113:deadline-monotonic scheduling 3602:10.1016/0166-5316(82)90024-4 3214:the system is determined to 3020:{\displaystyle U>U_{lub}} 2557:{\displaystyle U>U_{lub}} 2263:{\displaystyle U<U_{lub}} 436:{\displaystyle {n}\geq {10}} 4127:Highest response ratio next 3470:Dynamic priority scheduling 3027:, the system is determined 2564:, the system is determined 292:is the utilization factor, 120:Upper bounds on utilization 33:real-time operating systems 4301: 4107:Fixed-priority pre-emptive 3925:Buttazzo, Giorgio (2011), 3868:Buttazzo, Giorgio (2011), 3805:Buttazzo, Giorgio (2011), 3222:Harmonic Task Set Analysis 2058:The utilization will be: 1622:interrupt service routines 1616:Interrupt Service Routines 976:is an integer multiple of 66:blocking or non-blocking ( 4137:Multilevel feedback queue 4026:from Research @ Microsoft 3762:Communications of the ACM 1696:{\displaystyle {T_{isr}}} 1661:{\displaystyle {C_{isr}}} 1537:priority ceiling protocol 1337:{\displaystyle {K}{=}{1}} 1305:{\displaystyle {K}{=}{n}} 940:{\displaystyle i=1...m-1} 132:proved that for a set of 25:rate-monotonic scheduling 4142:Process Contention Scope 3929:, New York, NY: Springer 3823:. kernel.org. 2008-03-26 3649:10.1109/REAL.1991.160369 483:{\displaystyle {i^{th}}} 130:Liu & Layland (1973) 4167:Shortest remaining time 3981:10.1093/comjnl/29.5.390 3735:10.1109/TC.2003.1214341 3690:10.1109/REAL.1989.63567 1725:{\displaystyle {T_{1}}} 1473:Disabling of preemption 1027:{\displaystyle {T_{1}}} 998:{\displaystyle {T_{i}}} 969:{\displaystyle {T_{m}}} 859:{\displaystyle {T_{i}}} 830:{\displaystyle {T_{m}}} 541:{\displaystyle {T_{i}}} 512:{\displaystyle {C_{i}}} 3821:"Real-Time Linux Wiki" 3590:Performance Evaluation 3486:Scheduling (computing) 3443: 3414: 3269: 3208: 3177: 3069: 3021: 2978: 2907: 2830: 2720: 2606: 2558: 2515: 2444: 2367: 2264: 2222: 2145: 2120: 1961: 1909: 1857: 1776: 1726: 1697: 1662: 1424: 1391: 1338: 1306: 1267: 1200: 1142: 1028: 999: 970: 941: 906: 860: 831: 791: 679: 626: 542: 513: 484: 437: 404: 279: 212: 176: 4112:Foreground-background 3784:10.1145/358818.358824 3541:10.1145/321738.321743 3444: 3415: 3270: 3209: 3178: 3049: 3022: 2979: 2908: 2831: 2721: 2586: 2559: 2516: 2445: 2368: 2265: 2223: 2146: 2121: 1962: 1910: 1858: 1777: 1727: 1698: 1663: 1425: 1371: 1339: 1307: 1268: 1180: 1143: 1029: 1000: 971: 942: 907: 861: 832: 792: 680: 627: 543: 514: 485: 458:In practice, for the 438: 405: 280: 192: 156: 4073:Processor scheduling 3968:BCS Computer Journal 3684:, pp. 166–171, 3643:. pp. 160–170. 3427: 3290: 3230: 3190: 3046: 2992: 2923: 2843: 2819: 2583: 2529: 2460: 2380: 2356: 2235: 2158: 2134: 2065: 1919: 1867: 1786: 1736: 1707: 1672: 1637: 1501:Priority inheritance 1467:lock-free algorithms 1463:priority inheritance 1368: 1316: 1284: 1171: 1042: 1009: 980: 951: 916: 870: 841: 812: 707: 642: 589: 523: 494: 462: 417: 333: 320:U ≤ 0.8284 147: 4285:Real-time computing 4024:Mars Pathfinder Bug 2829:{\displaystyle 3\,} 2366:{\displaystyle 3\,} 2144:{\displaystyle 3\,} 1577:OS_ENTER_CRITICAL() 1480:OS_ENTER_CRITICAL() 1453:will be subject to 4254:Processor affinity 4147:Proportional share 4087:Deadline-monotonic 3574:2014-09-21 at the 3519:Journal of the ACM 3439: 3410: 3265: 3204: 3173: 3017: 2974: 2903: 2826: 2716: 2554: 2511: 2440: 2363: 2260: 2218: 2141: 2116: 1957: 1905: 1853: 1772: 1722: 1693: 1658: 1581:OS_EXIT_CRITICAL() 1522:2020-10-13 at the 1484:OS_EXIT_CRITICAL() 1455:priority inversion 1420: 1334: 1302: 1263: 1138: 1024: 995: 966: 937: 902: 856: 827: 787: 675: 622: 538: 509: 480: 451:or in cases where 433: 400: 351: 275: 4267: 4266: 4162:Shortest job next 4092:Earliest deadline 3958:Real-time systems 3946:978-0-321-41745-9 3699:978-0-8186-2004-1 3626:978-0-321-41745-9 3496:Kingman's formula 3392: 3359: 3156: 3131: 3106: 2966: 2953: 2940: 2885: 2811:Least Upper Bound 2805: 2804: 2747:Computation time 2693: 2668: 2643: 2503: 2490: 2477: 2422: 2348:Least Upper Bound 2342: 2341: 2284:Computation time 2200: 2108: 2095: 2082: 2054:Least Upper Bound 2048: 2047: 1990:Computation time 1863:will change from 1602: 1601: 1588:, highest locker 1348:Stochastic bounds 1223: 1141:{\displaystyle =} 1036:harmonic task set 772: 745: 673: 620: 569:interarrival time 368: 336: 235: 125:Least upper bound 4292: 4066: 4059: 4052: 4043: 4013: 3984: 3983: 3961: 3949: 3930: 3913: 3912: 3910: 3909: 3900:. Archived from 3894: 3888: 3887: 3880: 3874: 3873: 3865: 3859: 3857: 3855:10.1109/12.57058 3849:(9): 1175–1185, 3838: 3832: 3831: 3829: 3828: 3817: 3811: 3810: 3802: 3796: 3794: 3777: 3754: 3748: 3747: 3746: 3718: 3712: 3710: 3677: 3671: 3670: 3636: 3630: 3629: 3612: 3606: 3604: 3585: 3579: 3566: 3559: 3553: 3551: 3534: 3511: 3448: 3446: 3445: 3440: 3419: 3417: 3416: 3411: 3394: 3393: 3385: 3361: 3360: 3352: 3337: 3336: 3335: 3282: 3278: 3274: 3272: 3271: 3266: 3264: 3263: 3262: 3261: 3244: 3243: 3242: 3213: 3211: 3210: 3205: 3200: 3182: 3180: 3179: 3174: 3157: 3149: 3132: 3124: 3107: 3099: 3082: 3081: 3068: 3063: 3035:Hyperbolic Bound 3026: 3024: 3023: 3018: 3016: 3015: 2983: 2981: 2980: 2975: 2967: 2959: 2954: 2946: 2941: 2933: 2912: 2910: 2909: 2904: 2887: 2886: 2878: 2863: 2862: 2861: 2835: 2833: 2832: 2827: 2741: 2725: 2723: 2722: 2717: 2694: 2686: 2669: 2661: 2644: 2636: 2619: 2618: 2605: 2600: 2572:Hyperbolic Bound 2563: 2561: 2560: 2555: 2553: 2552: 2520: 2518: 2517: 2512: 2504: 2496: 2491: 2483: 2478: 2470: 2449: 2447: 2446: 2441: 2424: 2423: 2415: 2400: 2399: 2398: 2372: 2370: 2369: 2364: 2278: 2269: 2267: 2266: 2261: 2259: 2258: 2227: 2225: 2224: 2219: 2202: 2201: 2193: 2178: 2177: 2176: 2150: 2148: 2147: 2142: 2125: 2123: 2122: 2117: 2109: 2101: 2096: 2088: 2083: 2075: 1984: 1966: 1964: 1963: 1958: 1953: 1948: 1937: 1932: 1914: 1912: 1911: 1906: 1901: 1896: 1885: 1880: 1862: 1860: 1859: 1854: 1852: 1851: 1850: 1834: 1829: 1828: 1827: 1811: 1806: 1805: 1804: 1781: 1779: 1778: 1773: 1771: 1770: 1769: 1756: 1755: 1754: 1731: 1729: 1728: 1723: 1721: 1720: 1719: 1702: 1700: 1699: 1694: 1692: 1691: 1690: 1667: 1665: 1664: 1659: 1657: 1656: 1655: 1587: 1582: 1578: 1560: 1541:ceiling priority 1513:chained blocking 1495: 1485: 1481: 1445:Resource sharing 1440: 1429: 1427: 1426: 1421: 1404: 1403: 1390: 1385: 1357:Hyperbolic bound 1343: 1341: 1340: 1335: 1333: 1328: 1323: 1311: 1309: 1308: 1303: 1301: 1296: 1291: 1279: 1272: 1270: 1269: 1264: 1253: 1252: 1248: 1239: 1224: 1222: 1221: 1212: 1211: 1202: 1199: 1194: 1159: 1147: 1145: 1144: 1139: 1104: 1103: 1102: 1089: 1088: 1087: 1074: 1073: 1072: 1059: 1058: 1057: 1033: 1031: 1030: 1025: 1023: 1022: 1021: 1004: 1002: 1001: 996: 994: 993: 992: 975: 973: 972: 967: 965: 964: 963: 946: 944: 943: 938: 911: 909: 908: 903: 901: 900: 899: 889: 884: 883: 882: 865: 863: 862: 857: 855: 854: 853: 836: 834: 833: 828: 826: 825: 824: 796: 794: 793: 788: 786: 785: 773: 771: 770: 761: 760: 751: 746: 744: 743: 734: 733: 724: 719: 718: 699: 684: 682: 681: 676: 674: 672: 671: 659: 654: 653: 631: 629: 628: 623: 621: 619: 618: 606: 601: 600: 577: 566: 547: 545: 544: 539: 537: 536: 535: 518: 516: 515: 510: 508: 507: 506: 489: 487: 486: 481: 479: 478: 477: 454: 450: 446: 442: 440: 439: 434: 432: 424: 409: 407: 406: 401: 369: 367: 359: 350: 321: 317: 313: 309: 302: 298: 291: 284: 282: 281: 276: 265: 264: 260: 251: 236: 234: 233: 224: 223: 214: 211: 206: 188: 187: 186: 175: 170: 135: 21:computer science 4300: 4299: 4295: 4294: 4293: 4291: 4290: 4289: 4270: 4269: 4268: 4263: 4242: 4213:Completely Fair 4196: 4075: 4070: 4020: 4003:10.1109/2.55469 3988: 3965: 3952: 3947: 3934: 3924: 3921: 3919:Further reading 3916: 3907: 3905: 3896: 3895: 3891: 3882: 3881: 3877: 3867: 3866: 3862: 3840: 3839: 3835: 3826: 3824: 3819: 3818: 3814: 3804: 3803: 3799: 3756: 3755: 3751: 3720: 3719: 3715: 3700: 3679: 3678: 3674: 3659: 3638: 3637: 3633: 3627: 3614: 3613: 3609: 3587: 3586: 3582: 3576:Wayback Machine 3561: 3560: 3556: 3513: 3512: 3508: 3504: 3491:Queueing theory 3455: 3425: 3424: 3380: 3347: 3294: 3288: 3287: 3280: 3276: 3253: 3234: 3228: 3227: 3224: 3188: 3187: 3073: 3044: 3043: 3037: 3001: 2990: 2989: 2921: 2920: 2873: 2847: 2841: 2840: 2817: 2816: 2813: 2753:Release period 2739: 2610: 2581: 2580: 2574: 2538: 2527: 2526: 2458: 2457: 2410: 2384: 2378: 2377: 2354: 2353: 2350: 2290:Release period 2276: 2244: 2233: 2232: 2188: 2162: 2156: 2155: 2132: 2131: 2063: 2062: 2056: 1996:Release period 1982: 1977: 1917: 1916: 1865: 1864: 1836: 1813: 1790: 1784: 1783: 1761: 1740: 1734: 1733: 1711: 1705: 1704: 1676: 1670: 1669: 1641: 1635: 1634: 1630: 1618: 1610:Mars Pathfinder 1585: 1580: 1576: 1524:Wayback Machine 1517:real-time patch 1503: 1493: 1483: 1479: 1475: 1447: 1439: 1435: 1395: 1366: 1365: 1359: 1350: 1314: 1313: 1282: 1281: 1277: 1234: 1213: 1203: 1169: 1168: 1162:harmonic chains 1157: 1154: 1094: 1079: 1064: 1049: 1040: 1039: 1013: 1007: 1006: 984: 978: 977: 955: 949: 948: 914: 913: 891: 874: 868: 867: 845: 839: 838: 816: 810: 809: 806: 777: 762: 752: 735: 725: 710: 705: 704: 698: 694: 663: 645: 640: 639: 610: 592: 587: 586: 576: 572: 565: 561: 558:queueing theory 554: 527: 521: 520: 498: 492: 491: 466: 460: 459: 452: 448: 444: 415: 414: 331: 330: 319: 315: 311: 308: 304: 300: 297: 293: 289: 246: 225: 215: 178: 145: 144: 133: 127: 122: 105: 48: 17: 12: 11: 5: 4298: 4296: 4288: 4287: 4282: 4272: 4271: 4265: 4264: 4262: 4261: 4256: 4250: 4248: 4244: 4243: 4241: 4240: 4235: 4230: 4228:SCHED DEADLINE 4225: 4220: 4215: 4210: 4204: 4202: 4198: 4197: 4195: 4194: 4189: 4184: 4179: 4174: 4169: 4164: 4159: 4154: 4152:Rate-monotonic 4149: 4144: 4139: 4134: 4129: 4124: 4119: 4114: 4109: 4104: 4099: 4094: 4089: 4083: 4081: 4077: 4076: 4071: 4069: 4068: 4061: 4054: 4046: 4040: 4039: 4033: 4027: 4019: 4018:External links 4016: 4015: 4014: 3986: 3974:(5): 390–395, 3963: 3954:Liu, Jane W.S. 3950: 3945: 3932: 3920: 3917: 3915: 3914: 3889: 3875: 3860: 3833: 3812: 3797: 3775:10.1.1.46.7240 3768:(2): 105–117, 3758:Lampson, B. W. 3749: 3729:(7): 933–942, 3713: 3698: 3672: 3657: 3631: 3625: 3607: 3596:(4): 237–250, 3580: 3554: 3532:10.1.1.36.8216 3505: 3503: 3500: 3499: 3498: 3493: 3488: 3483: 3477: 3472: 3467: 3461: 3454: 3451: 3438: 3435: 3432: 3421: 3420: 3409: 3406: 3403: 3400: 3397: 3391: 3388: 3383: 3379: 3376: 3373: 3370: 3367: 3364: 3358: 3355: 3350: 3346: 3343: 3340: 3334: 3331: 3328: 3325: 3322: 3319: 3316: 3313: 3310: 3307: 3304: 3301: 3297: 3260: 3256: 3251: 3247: 3241: 3237: 3223: 3220: 3203: 3199: 3195: 3184: 3183: 3172: 3169: 3166: 3163: 3160: 3155: 3152: 3147: 3144: 3141: 3138: 3135: 3130: 3127: 3122: 3119: 3116: 3113: 3110: 3105: 3102: 3097: 3094: 3091: 3088: 3085: 3080: 3076: 3072: 3067: 3062: 3059: 3056: 3052: 3036: 3033: 3014: 3011: 3008: 3004: 3000: 2997: 2986: 2985: 2973: 2970: 2965: 2962: 2957: 2952: 2949: 2944: 2939: 2936: 2931: 2928: 2914: 2913: 2902: 2899: 2896: 2893: 2890: 2884: 2881: 2876: 2872: 2869: 2866: 2860: 2857: 2854: 2850: 2824: 2812: 2809: 2803: 2802: 2799: 2796: 2793: 2789: 2788: 2785: 2782: 2779: 2775: 2774: 2771: 2768: 2765: 2761: 2760: 2757: 2751: 2745: 2738: 2735: 2727: 2726: 2715: 2712: 2709: 2706: 2703: 2700: 2697: 2692: 2689: 2684: 2681: 2678: 2675: 2672: 2667: 2664: 2659: 2656: 2653: 2650: 2647: 2642: 2639: 2634: 2631: 2628: 2625: 2622: 2617: 2613: 2609: 2604: 2599: 2596: 2593: 2589: 2573: 2570: 2551: 2548: 2545: 2541: 2537: 2534: 2523: 2522: 2510: 2507: 2502: 2499: 2494: 2489: 2486: 2481: 2476: 2473: 2468: 2465: 2451: 2450: 2439: 2436: 2433: 2430: 2427: 2421: 2418: 2413: 2409: 2406: 2403: 2397: 2394: 2391: 2387: 2361: 2349: 2346: 2340: 2339: 2336: 2333: 2330: 2326: 2325: 2322: 2319: 2316: 2312: 2311: 2308: 2305: 2302: 2298: 2297: 2294: 2288: 2282: 2275: 2272: 2257: 2254: 2251: 2247: 2243: 2240: 2229: 2228: 2217: 2214: 2211: 2208: 2205: 2199: 2196: 2191: 2187: 2184: 2181: 2175: 2172: 2169: 2165: 2139: 2128: 2127: 2115: 2112: 2107: 2104: 2099: 2094: 2091: 2086: 2081: 2078: 2073: 2070: 2055: 2052: 2046: 2045: 2042: 2039: 2036: 2032: 2031: 2028: 2025: 2022: 2018: 2017: 2014: 2011: 2008: 2004: 2003: 2000: 1994: 1988: 1981: 1978: 1976: 1973: 1956: 1952: 1947: 1944: 1941: 1936: 1931: 1928: 1925: 1904: 1900: 1895: 1892: 1889: 1884: 1879: 1876: 1873: 1849: 1846: 1843: 1839: 1833: 1826: 1823: 1820: 1816: 1810: 1803: 1800: 1797: 1793: 1768: 1764: 1759: 1753: 1750: 1747: 1743: 1718: 1714: 1689: 1686: 1683: 1679: 1654: 1651: 1648: 1644: 1629: 1626: 1617: 1614: 1600: 1599: 1596: 1594: 1590: 1589: 1583: 1574: 1570: 1569: 1566: 1563: 1554: 1553: 1532: 1531: 1502: 1499: 1498: 1497: 1490: 1474: 1471: 1446: 1443: 1437: 1432: 1431: 1419: 1416: 1413: 1410: 1407: 1402: 1398: 1394: 1389: 1384: 1381: 1378: 1374: 1358: 1355: 1349: 1346: 1332: 1327: 1322: 1300: 1295: 1290: 1274: 1273: 1262: 1259: 1256: 1251: 1247: 1243: 1238: 1233: 1230: 1227: 1220: 1216: 1210: 1206: 1198: 1193: 1190: 1187: 1183: 1179: 1176: 1153: 1150: 1137: 1134: 1131: 1128: 1125: 1122: 1119: 1116: 1113: 1110: 1107: 1101: 1097: 1092: 1086: 1082: 1077: 1071: 1067: 1062: 1056: 1052: 1047: 1020: 1016: 991: 987: 962: 958: 936: 933: 930: 927: 924: 921: 898: 894: 888: 881: 877: 852: 848: 823: 819: 805: 802: 798: 797: 784: 780: 776: 769: 765: 759: 755: 749: 742: 738: 732: 728: 722: 717: 713: 696: 691: 690: 670: 666: 662: 657: 652: 648: 637: 617: 613: 609: 604: 599: 595: 578:is called the 574: 567:is called the 563: 553: 550: 534: 530: 505: 501: 476: 473: 469: 431: 427: 423: 411: 410: 399: 396: 393: 390: 387: 384: 381: 378: 375: 372: 366: 362: 357: 354: 349: 346: 343: 339: 306: 295: 286: 285: 274: 271: 268: 263: 259: 255: 250: 245: 242: 239: 232: 228: 222: 218: 210: 205: 202: 199: 195: 191: 185: 181: 174: 169: 166: 163: 159: 155: 152: 126: 123: 121: 118: 104: 101: 88: 87: 84: 81:rate monotonic 77: 74: 71: 47: 44: 15: 13: 10: 9: 6: 4: 3: 2: 4297: 4286: 4283: 4281: 4278: 4277: 4275: 4260: 4257: 4255: 4252: 4251: 4249: 4245: 4239: 4236: 4234: 4231: 4229: 4226: 4224: 4221: 4219: 4216: 4214: 4211: 4209: 4206: 4205: 4203: 4199: 4193: 4192:YDS algorithm 4190: 4188: 4185: 4183: 4180: 4178: 4175: 4173: 4170: 4168: 4165: 4163: 4160: 4158: 4155: 4153: 4150: 4148: 4145: 4143: 4140: 4138: 4135: 4133: 4130: 4128: 4125: 4123: 4120: 4118: 4115: 4113: 4110: 4108: 4105: 4103: 4100: 4098: 4095: 4093: 4090: 4088: 4085: 4084: 4082: 4078: 4074: 4067: 4062: 4060: 4055: 4053: 4048: 4047: 4044: 4036: 4034: 4031: 4028: 4025: 4022: 4021: 4017: 4012: 4008: 4004: 4000: 3996: 3992: 3991:IEEE Computer 3987: 3982: 3977: 3973: 3969: 3964: 3959: 3955: 3951: 3948: 3942: 3938: 3933: 3928: 3923: 3922: 3918: 3904:on 2011-10-05 3903: 3899: 3893: 3890: 3885: 3879: 3876: 3871: 3864: 3861: 3856: 3852: 3848: 3844: 3837: 3834: 3822: 3816: 3813: 3808: 3801: 3798: 3793: 3789: 3785: 3781: 3776: 3771: 3767: 3763: 3759: 3753: 3750: 3745: 3740: 3736: 3732: 3728: 3724: 3717: 3714: 3709: 3705: 3701: 3695: 3691: 3687: 3683: 3676: 3673: 3668: 3664: 3660: 3658:0-8186-2450-7 3654: 3650: 3646: 3642: 3635: 3632: 3628: 3622: 3618: 3611: 3608: 3603: 3599: 3595: 3591: 3584: 3581: 3577: 3573: 3570: 3565: 3558: 3555: 3550: 3546: 3542: 3538: 3533: 3528: 3524: 3520: 3516: 3510: 3507: 3501: 3497: 3494: 3492: 3489: 3487: 3484: 3481: 3478: 3476: 3473: 3471: 3468: 3465: 3462: 3460: 3457: 3456: 3452: 3450: 3436: 3433: 3430: 3407: 3404: 3398: 3395: 3389: 3386: 3381: 3374: 3371: 3365: 3362: 3356: 3353: 3348: 3341: 3338: 3332: 3329: 3326: 3323: 3320: 3317: 3314: 3311: 3308: 3305: 3302: 3299: 3295: 3286: 3285: 3284: 3258: 3254: 3249: 3245: 3239: 3235: 3221: 3219: 3217: 3201: 3197: 3193: 3170: 3167: 3161: 3158: 3153: 3150: 3142: 3136: 3133: 3128: 3125: 3117: 3111: 3108: 3103: 3100: 3092: 3086: 3083: 3078: 3074: 3065: 3060: 3057: 3054: 3050: 3042: 3041: 3040: 3034: 3032: 3030: 3012: 3009: 3006: 3002: 2998: 2995: 2971: 2968: 2963: 2960: 2955: 2950: 2947: 2942: 2937: 2934: 2929: 2926: 2919: 2918: 2917: 2900: 2897: 2891: 2888: 2882: 2879: 2874: 2867: 2864: 2858: 2855: 2852: 2848: 2839: 2838: 2837: 2822: 2810: 2808: 2800: 2797: 2794: 2791: 2790: 2786: 2783: 2780: 2777: 2776: 2772: 2769: 2766: 2763: 2762: 2758: 2756: 2752: 2750: 2746: 2743: 2742: 2736: 2734: 2733:schedulable. 2732: 2713: 2710: 2707: 2704: 2698: 2695: 2690: 2687: 2679: 2673: 2670: 2665: 2662: 2654: 2648: 2645: 2640: 2637: 2629: 2623: 2620: 2615: 2611: 2602: 2597: 2594: 2591: 2587: 2579: 2578: 2577: 2571: 2569: 2567: 2549: 2546: 2543: 2539: 2535: 2532: 2508: 2505: 2500: 2497: 2492: 2487: 2484: 2479: 2474: 2471: 2466: 2463: 2456: 2455: 2454: 2437: 2434: 2428: 2425: 2419: 2416: 2411: 2404: 2401: 2395: 2392: 2389: 2385: 2376: 2375: 2374: 2359: 2347: 2345: 2337: 2334: 2331: 2328: 2327: 2323: 2320: 2317: 2314: 2313: 2309: 2306: 2303: 2300: 2299: 2295: 2293: 2289: 2287: 2283: 2280: 2279: 2273: 2271: 2255: 2252: 2249: 2245: 2241: 2238: 2215: 2212: 2206: 2203: 2197: 2194: 2189: 2182: 2179: 2173: 2170: 2167: 2163: 2154: 2153: 2152: 2137: 2113: 2110: 2105: 2102: 2097: 2092: 2089: 2084: 2079: 2076: 2071: 2068: 2061: 2060: 2059: 2053: 2051: 2043: 2040: 2037: 2034: 2033: 2029: 2026: 2023: 2020: 2019: 2015: 2012: 2009: 2006: 2005: 2001: 1999: 1995: 1993: 1989: 1986: 1985: 1979: 1974: 1972: 1968: 1954: 1950: 1945: 1942: 1939: 1934: 1929: 1926: 1923: 1902: 1898: 1893: 1890: 1887: 1882: 1877: 1874: 1871: 1847: 1844: 1841: 1837: 1831: 1824: 1821: 1818: 1814: 1808: 1801: 1798: 1795: 1791: 1766: 1762: 1757: 1751: 1748: 1745: 1741: 1716: 1712: 1687: 1684: 1681: 1677: 1652: 1649: 1646: 1642: 1627: 1625: 1623: 1615: 1613: 1611: 1606: 1597: 1595: 1592: 1591: 1584: 1575: 1572: 1571: 1567: 1564: 1562: 1561: 1558: 1551: 1547: 1542: 1538: 1534: 1533: 1529: 1525: 1521: 1518: 1514: 1509: 1505: 1504: 1500: 1491: 1489: 1477: 1476: 1472: 1470: 1468: 1464: 1460: 1456: 1452: 1444: 1442: 1417: 1414: 1408: 1405: 1400: 1396: 1387: 1382: 1379: 1376: 1372: 1364: 1363: 1362: 1356: 1354: 1347: 1345: 1330: 1325: 1320: 1298: 1293: 1288: 1257: 1254: 1249: 1245: 1241: 1236: 1228: 1225: 1218: 1214: 1208: 1204: 1196: 1191: 1188: 1185: 1181: 1177: 1174: 1167: 1166: 1165: 1163: 1151: 1149: 1132: 1129: 1126: 1123: 1120: 1117: 1114: 1108: 1099: 1095: 1090: 1084: 1080: 1075: 1069: 1065: 1060: 1054: 1050: 1037: 1018: 1014: 989: 985: 960: 956: 934: 931: 928: 925: 922: 919: 896: 892: 886: 879: 875: 850: 846: 821: 817: 803: 801: 782: 778: 774: 767: 763: 757: 753: 747: 740: 736: 730: 726: 720: 715: 711: 703: 702: 701: 688: 668: 664: 660: 655: 650: 646: 638: 635: 615: 611: 607: 602: 597: 593: 585: 584: 583: 581: 570: 559: 551: 549: 532: 528: 503: 499: 474: 471: 467: 456: 429: 425: 421: 397: 394: 391: 388: 385: 382: 379: 373: 370: 364: 360: 352: 341: 329: 328: 327: 325: 269: 266: 261: 257: 253: 248: 240: 237: 230: 226: 220: 216: 208: 203: 200: 197: 193: 189: 183: 179: 172: 167: 164: 161: 157: 153: 150: 143: 142: 141: 139: 131: 124: 119: 117: 114: 110: 102: 100: 97: 93: 85: 82: 78: 75: 72: 69: 65: 61: 57: 53: 52: 51: 45: 43: 41: 36: 34: 30: 26: 22: 4238:SCHED NORMAL 4151: 3997:(4): 53–62, 3994: 3990: 3971: 3967: 3962:, Chapter 6. 3957: 3936: 3926: 3906:. Retrieved 3902:the original 3892: 3878: 3869: 3863: 3846: 3842: 3836: 3825:. Retrieved 3815: 3806: 3800: 3765: 3761: 3752: 3744:11382/200358 3726: 3722: 3716: 3681: 3675: 3640: 3634: 3616: 3610: 3593: 3589: 3583: 3563: 3557: 3525:(1): 46–61, 3522: 3518: 3509: 3422: 3225: 3215: 3185: 3038: 3028: 2987: 2915: 2814: 2806: 2754: 2748: 2730: 2728: 2575: 2565: 2524: 2452: 2351: 2343: 2291: 2285: 2230: 2129: 2057: 2049: 1997: 1991: 1969: 1631: 1619: 1607: 1603: 1565:pessimistic 1555: 1549: 1540: 1528:Linux kernel 1512: 1507: 1488:MicroC/OS-II 1450: 1448: 1433: 1360: 1351: 1275: 1161: 1155: 807: 799: 692: 687:service rate 686: 634:arrival rate 633: 580:service time 579: 568: 555: 457: 412: 287: 128: 108: 106: 96:time-sharing 89: 80: 55: 49: 46:Introduction 37: 28: 24: 18: 4157:Round-robin 1568:optimistic 700:, is then: 92:round-robin 4274:Categories 4259:Starvation 4233:SCHED FIFO 4208:Brain Fuck 4187:Windows NT 4102:Fair-share 4080:Algorithms 3908:2008-09-09 3827:2014-03-14 3515:Liu, C. L. 3502:References 1573:immediate 800:as above. 103:Optimality 68:busy-waits 40:preemptive 4182:Two-level 3770:CiteSeerX 3708:206524469 3549:207669821 3527:CiteSeerX 3396:− 3363:− 3143:∗ 3118:∗ 3051:∏ 2889:− 2759:Priority 2737:Example 3 2711:≤ 2680:∗ 2655:∗ 2588:∏ 2426:− 2296:Priority 2274:Example 2 2204:− 2002:Priority 1980:Example 1 1415:≤ 1373:∏ 1255:− 1226:≤ 1182:∑ 932:− 737:μ 727:λ 712:ρ 647:μ 594:λ 490:process, 426:≥ 398:… 392:≈ 386:⁡ 371:− 348:∞ 345:→ 267:− 238:≤ 194:∑ 158:∑ 64:semaphore 4038:problem. 4011:12647942 3956:(2000), 3667:31127772 3572:Archived 3453:See also 3226:Because 2744:Process 2281:Process 2231:Because 1987:Process 1975:Examples 1520:Archived 1459:deadlock 395:0.693147 324:infinity 60:hardware 4132:Lottery 3792:1594544 3431:0.81875 2972:0.81875 2901:0.77976 2438:0.77976 2216:0.77976 1546:VxWorks 1526:to the 685:is the 632:is the 109:optimal 4177:Stride 4009:  3943:  3790:  3772:  3706:  3696:  3665:  3655:  3623:  3547:  3529:  3202:2.0475 3186:Since 3171:2.0475 2988:Since 2525:Since 2509:0.7875 1586:splx() 1552:(HLP). 1494:splx() 1434:where 866:where 695:ρ 571:, and 314:, and 288:where 4247:Other 4201:Linux 4007:S2CID 3788:S2CID 3704:S2CID 3663:S2CID 3545:S2CID 3480:RTEMS 3437:0.828 3408:0.828 3279:, is 2708:1.995 2114:0.725 1903:0.125 1593:lazy 636:, and 4223:O(n) 4218:O(1) 4117:Gang 3941:ISBN 3694:ISBN 3653:ISBN 3621:ISBN 3464:Deos 3434:< 3198:< 2999:> 2536:> 2242:< 1620:All 1535:The 1506:The 1492:The 1482:and 1478:The 1457:and 926:1... 912:and 887:> 94:and 56:e.g. 3999:doi 3976:doi 3851:doi 3780:doi 3739:hdl 3731:doi 3686:doi 3645:doi 3598:doi 3537:doi 3216:not 3194:2.0 3029:not 2798:10 2792:P3 2778:P2 2770:32 2764:P1 2566:not 2335:10 2329:P3 2315:P2 2307:16 2301:P1 2041:10 2035:P3 2021:P2 2007:P1 1955:0.5 1924:0.5 1915:to 1872:0.5 1451:RMS 556:In 338:lim 138:CPU 29:RMS 19:In 4276:: 4005:, 3995:23 3993:, 3972:29 3970:, 3847:39 3845:, 3786:, 3778:, 3766:23 3764:, 3737:, 3727:52 3725:, 3702:, 3692:, 3661:. 3651:. 3592:, 3567:, 3543:, 3535:, 3523:20 3521:, 3283:. 3154:10 3104:32 2964:10 2938:32 2801:2 2795:2 2787:1 2784:5 2781:2 2773:3 2767:7 2731:is 2691:10 2641:16 2501:10 2475:16 2338:2 2332:2 2324:1 2321:5 2318:2 2310:3 2304:3 2106:10 2044:3 2038:2 2030:1 2027:5 2024:2 2016:2 2013:8 2010:1 1579:/ 1133:12 947:, 837:, 560:, 430:10 383:ln 303:, 70:)) 58:a 23:, 4065:e 4058:t 4051:v 4001:: 3985:. 3978:: 3931:. 3911:. 3886:. 3858:. 3853:: 3830:. 3795:. 3782:: 3741:: 3733:: 3711:. 3688:: 3669:. 3647:: 3605:. 3600:: 3594:2 3578:. 3552:. 3539:: 3405:= 3402:) 3399:1 3390:2 3387:1 3382:2 3378:( 3375:2 3372:= 3369:) 3366:1 3357:K 3354:1 3349:2 3345:( 3342:K 3339:= 3333:c 3330:i 3327:n 3324:o 3321:m 3318:r 3315:a 3312:h 3309:, 3306:b 3303:u 3300:l 3296:U 3281:2 3277:K 3259:2 3255:T 3250:2 3246:= 3240:3 3236:T 3168:= 3165:) 3162:1 3159:+ 3151:2 3146:( 3140:) 3137:1 3134:+ 3129:5 3126:2 3121:( 3115:) 3112:1 3109:+ 3101:7 3096:( 3093:= 3090:) 3087:1 3084:+ 3079:i 3075:U 3071:( 3066:n 3061:1 3058:= 3055:i 3013:b 3010:u 3007:l 3003:U 2996:U 2984:. 2969:= 2961:2 2956:+ 2951:5 2948:2 2943:+ 2935:7 2930:= 2927:U 2898:= 2895:) 2892:1 2883:3 2880:1 2875:2 2871:( 2868:3 2865:= 2859:b 2856:u 2853:l 2849:U 2823:3 2755:T 2749:C 2714:2 2705:= 2702:) 2699:1 2696:+ 2688:2 2683:( 2677:) 2674:1 2671:+ 2666:5 2663:2 2658:( 2652:) 2649:1 2646:+ 2638:3 2633:( 2630:= 2627:) 2624:1 2621:+ 2616:i 2612:U 2608:( 2603:n 2598:1 2595:= 2592:i 2550:b 2547:u 2544:l 2540:U 2533:U 2521:. 2506:= 2498:2 2493:+ 2488:5 2485:2 2480:+ 2472:3 2467:= 2464:U 2435:= 2432:) 2429:1 2420:3 2417:1 2412:2 2408:( 2405:3 2402:= 2396:b 2393:u 2390:l 2386:U 2360:3 2292:T 2286:C 2256:b 2253:u 2250:l 2246:U 2239:U 2213:= 2210:) 2207:1 2198:3 2195:1 2190:2 2186:( 2183:3 2180:= 2174:b 2171:u 2168:l 2164:U 2138:3 2126:. 2111:= 2103:2 2098:+ 2093:5 2090:2 2085:+ 2080:8 2077:1 2072:= 2069:U 1998:T 1992:C 1951:= 1946:s 1943:m 1940:1 1935:/ 1930:s 1927:m 1899:= 1894:s 1891:m 1888:4 1883:/ 1878:s 1875:m 1848:r 1845:s 1842:i 1838:T 1832:/ 1825:r 1822:s 1819:i 1815:C 1809:= 1802:r 1799:s 1796:i 1792:U 1767:1 1763:T 1758:= 1752:r 1749:s 1746:i 1742:T 1717:1 1713:T 1688:r 1685:s 1682:i 1678:T 1653:r 1650:s 1647:i 1643:C 1438:i 1436:U 1430:, 1418:2 1412:) 1409:1 1406:+ 1401:i 1397:U 1393:( 1388:n 1383:1 1380:= 1377:i 1331:1 1326:= 1321:K 1299:n 1294:= 1289:K 1278:n 1261:) 1258:1 1250:K 1246:/ 1242:1 1237:2 1232:( 1229:K 1219:i 1215:T 1209:i 1205:C 1197:n 1192:1 1189:= 1186:i 1178:= 1175:U 1158:K 1136:] 1130:, 1127:6 1124:, 1121:3 1118:, 1115:1 1112:[ 1109:= 1106:] 1100:4 1096:T 1091:, 1085:3 1081:T 1076:, 1070:2 1066:T 1061:, 1055:1 1051:T 1046:[ 1019:1 1015:T 990:i 986:T 961:m 957:T 935:1 929:m 923:= 920:i 897:i 893:T 880:m 876:T 851:i 847:T 822:m 818:T 783:i 779:U 775:= 768:i 764:T 758:i 754:C 748:= 741:i 731:i 721:= 716:i 697:i 689:. 669:i 665:C 661:1 656:= 651:i 616:i 612:T 608:1 603:= 598:i 575:i 573:C 564:i 562:T 533:i 529:T 504:i 500:C 475:h 472:t 468:i 453:U 449:n 445:U 422:n 389:2 380:= 377:) 374:1 365:n 361:2 356:( 353:n 342:n 316:n 312:i 307:i 305:T 301:i 296:i 294:C 290:U 273:) 270:1 262:n 258:/ 254:1 249:2 244:( 241:n 231:i 227:T 221:i 217:C 209:n 204:1 201:= 198:i 190:= 184:i 180:U 173:n 168:1 165:= 162:i 154:= 151:U 134:n 27:(

Index

computer science
real-time operating systems
preemptive
hardware
semaphore
busy-waits
round-robin
time-sharing
deadline-monotonic scheduling
Liu & Layland (1973)
CPU
infinity
queueing theory
harmonic task set
priority inversion
deadlock
priority inheritance
lock-free algorithms
MicroC/OS-II
real-time patch
Archived
Wayback Machine
Linux kernel
priority ceiling protocol
VxWorks
Mars Pathfinder
interrupt service routines
Deadline-monotonic scheduling
Deos
Dynamic priority scheduling

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