Nathan Russell Tallent

E-mail:	tallent at pnnl dot gov
Office:	CSF 1720
Telephone:	509.372.4206
Home Page:	https://hpc.pnnl.gov/people/tallent https://www.pnnl.gov/people/nathan-tallent [google scholar] [research gate]
Postal Address:	Pacific Northwest National Laboratory PO Box 999 MSIN: J4-30 Richland WA 99352
Delivery Address:	Pacific Northwest National Laboratory 902 Battelle Blvd MS-J4-30 Richland, WA 99354

Nathan Tallent is a computer scientist and lead for the Scalable Computing & Data team in the High Performance Computing Group within the Advanced Computing, Mathematics, and Data Division. He joined PNNL in 2011. He received a Ph.D. in 2010 from Rice University.

His research is in the areas of performance analysis, parallelism, scalable and distributed architectures, and data-intensive analytics. His work spans the challenges of characterizing, modeling, analyzing, and accelerating the performance of current and emerging workloads in scientific workflows, data analytics, and domain modeling. His recent work has focused on exploiting dynamic inter-task data locality and minimizing data movement through storage, network, and memory. He is also interested in performance tools, models, and techniques for bottleneck diagnosis, online adaptation, and hardware-software co-design. A recent theme has been lightweight and scalable techniques for workloads with irregular parallelism, data structures, and access patterns.

He has led development of the following research software prototypes:

• TAZeR: TAZeR is a remote I/O framework for transparently minimizing the access latencies of remote I/O in workflows. TAZeR's primary strategy is capturing dynamic and irregular inter-task locality, both temporal and spatial, via adaptive hierarchical staging that ensures most frequently accessed data is `close'.
• BigFlowSim: BigFlowSim is a workflow I/O simulator-emulator and trace generator that captures several parameters that affect local and remote I/O performance. BigFlowSim generates a large variety of flows within and between tasks of distributed workflows. With BigFlowSim, we have systematically studied TAZeR's performance on different data flows.
• Palm: Palm is a suite of performance modeling tools (Palm, Palm-Task, Representative-Paths, Palm/FastFootprints, MIAMI-NW) to assist performance analysis and predictive model generation. Palm generates models by combining top-down (human-provided) semantic insight with bottom-up static and dynamic analysis. Palm has been used to model irregular applications with sparse data structures and unpredictable access patterns. Recent additions focus on rapid characterization of memory behavior.
• SEAK Suite: The SEAK Suite is a collection of constraining problems for common embedded computing challenges. A constraining problem is a mission-centric and goal-oriented problem specification that separate problem-domain constraints from solution implementations so as to encourage creative solutions that meet goals but that may deviate from standard implementations.
• PERFECT Suite: The PERFECT Suite consists of kernels and applications for evaluating tradeoffs between performance, power, and architecture within the domains of radar and image processing.

He is one of the original developers of HPCToolkit, a widely used suite of performance tools on supercomputers.

He contributed to OpenAD, a tool for automatic differentiation (AD) of numerical computer programs.