| 1. |
- Nemati, Farhang, et al.
(författare)
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A Framework for Real-Time Systems Migration to Multi-Cores
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Power consumption and thermal problems limit a further increase of speed in single-core processors. Processor architects are therefore moving toward multicore processors. However, a shift to multi-core processors is a big challenge for developers of embedded real-time systems, especially considering existing “legacy†systems which have been developed with single-core processor assumptions. These systems have been developed and maintained by many developers over many years, and cannot easily be replaced due to the huge development investments they represent. In this paper we investigate challenges of migrating complex legacy real-time systems to multi-core architectures. We propose a partitioning algorithm to prepare the migration. Partitioning groups task and maps them to the different cores on the multicore processor, increasing system performance while ensuring correctness. We have run experiments that compare outputs of the algorithm to the outputs of an exhaustive search. Based on a cost function, the algorithm produces systems very close to optimal partitioning with respect to the cost function.
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| 2. |
- Nemati, Farhang, et al.
(författare)
-
Blocking-Aware Partitioning for Multiprocessors
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the multi-core and multiprocessor domain there are two scheduling approaches, global and partitioned scheduling. Under global scheduling each task can execute on any processor while under partitioned scheduling tasks are allocated to processors and migration of tasks among processors is not allowed. Under global scheduling the higher utilization bound can be achieved, but in practice the overheads of migrating tasks is high. On the other hand, besides simplicity and efficiency of partitioned scheduling protocols, existing scheduling and synchronization methods developed for uniprocessor platforms can more easily be extended to partitioned scheduling. This also simplifies migration of existing systems to multi-cores. An important issue related to partitioned scheduling is how to distribute tasks among processors/cores to increase performance offered by the platform. However, existing methods mostly assume independent tasks while in practice a typical real-time system contains tasks that share resources and they may block each other. In this paper we propose a blocking-aware partitioning algorithm to distribute tasks onto different processors. The proposed algorithm allocates a task set onto processors in a way that blocking times of tasks are decreased. This reduces the total utilization which has the potential to decrease the total number of needed processors/cores.
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| 3. |
- Nemati, Farhang, et al.
(författare)
-
Resource Sharing among Prioritized Real-Time Applications on Multi-cores
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- MSOS (Multiprocessors Synchronization protocol for real-time Open Systems) is a synchronization protocol for handling resource sharing among independently-developed realtime applications (components) on multi-core platforms. MSOS does not consider any priority setting among applications. To handle resource sharing based on the priority of applications, in this paper we propose a new protocol that allows for resource sharing among prioritized real-time applications on a multi-core platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the existing MSOS as well as to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP and OMLP. The evaluations show that MSOS-Priority mostly performs significantly better than alternative approaches.
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