Computer System Performance Evaluation Using Queueing Network Models

Analytic model of a Cache Only Memory Architecture

“…The comparison shows that the error introduced by the approximate model is acceptable specially if the system is not saturated, which is the desirable condition. In this case, errors are inside the expected bounds established in [7] (30% for response times and 10% for utilizations) in more than 90% of the simulations.…”

“…If total numbers from Table 2 are analyzed, the errors in system response times (T avg ) for most configurations (97%) are well within the 30% margin defined in [7] as acceptable. Errors in device utilizations are acceptable if they are within a 10% margin around the simulated valúes.…”

Parallel Interconnection of Broadcast Systems with Multiple FIFO Channels

“…Thus, with a negligible workload, the optimal number of IS processes per system is 1, since this eliminates the need of a synchronisation (intra-system) message (i.e., that carrying the sequence number), as it can be seen in expression (3). However, when workload is considered, we could use a queueing model [17] in order to represent such system, but as it is already mentioned in [17,Chapter 5], in a queueing network we only need to identify its bottleneck centre in order to set upper bounds to the global system throughput. In our system, and with the assumptions given above, such bottleneck centre is the interconnecting channel.…”

Uma metodologia para desenvolvimento de programas paralelos eficientes em ambientes homogêneos e heterogêneos.

“…Já as redes de filas, definidas como um subconjunto da teoria de filas, são aplicadas na modelagem de sistemas computacionais (LAZOWSKA et al, 1984). As técnicas que constituem essas teorias acabam formando uma ferramenta matemática importante para avaliações quantitativas de sistemas.…”

“…No entanto, esse problemaé menor quando o domínio de aplicaçãoé o computacional. Segundo descrito em (LAZOWSKA et al, 1984), algoritmos precisos para avaliação de desempenho podem ser elaborados ponderando custo e complexidade.…”