real-time systems for multi-processor architectures
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1.1 Multi-Processing and Real-time Ap-proaches
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1.2 Real-time With Linux
2.1 Partition of the Processors and Pro-cesses
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load
balancingload
balancing
cluster
migrationARTiS
migrationARTiS
RT1+
RT CPURT CPURT CPUNRT CPU
RT0
Linux
Figure 1. Example of a typical usage of a system based on ARTiS. The application is separated alongdifferent levels of real-time priorities. Tasks are moved by the ARTiS mechanisms of migration andload-balancing.
2.2 Migration Mechanism
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2.3 Load-Balancing Policy
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Time
NRT CPU
RT CPU
Figure 2. The so-called ping-pong problem. A task running on a NRT CPU will be migrated by theload-balancer to a, less loaded, RT CPU. Due to frequent interrupt deactivation, it soon goes back toa NRT CPU.
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Forbidden migration to RT CPU
Figure 3. Period of forbidden migration (hatched rectangle). The period is deducted from the studyof the previous behavior of the given task.
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2.4 System and Application Deployment
3.1 Latency Measurement
3.2 Execution Time Variation
Table 1. Maximum Kernel/User latencies of the different configurations.
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Tmin
Tmin
Tmin
3.3 Load-balancing Observation
Figure 4. Extract of an lb scenario definition
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