37,076 research outputs found
OS Scheduling Algorithms for Memory Intensive Workloads in Multi-socket Multi-core servers
Major chip manufacturers have all introduced multicore microprocessors.
Multi-socket systems built from these processors are routinely used for running
various server applications. Depending on the application that is run on the
system, remote memory accesses can impact overall performance. This paper
presents a new operating system (OS) scheduling optimization to reduce the
impact of such remote memory accesses. By observing the pattern of local and
remote DRAM accesses for every thread in each scheduling quantum and applying
different algorithms, we come up with a new schedule of threads for the next
quantum. This new schedule potentially cuts down remote DRAM accesses for the
next scheduling quantum and improves overall performance. We present three such
new algorithms of varying complexity followed by an algorithm which is an
adaptation of Hungarian algorithm. We used three different synthetic workloads
to evaluate the algorithm. We also performed sensitivity analysis with respect
to varying DRAM latency. We show that these algorithms can cut down DRAM access
latency by up to 55% depending on the algorithm used. The benefit gained from
the algorithms is dependent upon their complexity. In general higher the
complexity higher is the benefit. Hungarian algorithm results in an optimal
solution. We find that two out of four algorithms provide a good trade-off
between performance and complexity for the workloads we studied
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