Performance Modelling · AI systems · Distributed Computing · Photonic Computing

Sairam Sri Vatsavai

Assistant Computational Scientist, Computational and Data Sciences Department,
Brookhaven National Laboratory · Upton, New York

My research focuses on understanding and improving computing systems across two complementary fronts. First, I evaluate emerging computing technologies like superconducting digital logic , photonics and in-memory computing , by developing analytical and AI-enabled modeling frameworks that characterize their performance, identify their potential, and enable exploration of the cross-layer design space spanning device, architecture, and applications. Second, I study existing large-scale distributed computing systems for scientific workflows, with an emphasis on improving their resilience and efficiency through better workload modeling, scheduling, and resource-management policies. Together, these efforts aim to build principled tools for understanding both future computing platforms and the complex systems that support large-scale science today.

Before joining Brookhaven National Laboratory, I completed my Ph.D. in Electrical Engineering at the UCAT Lab at the University of Kentucky in spring 2024, under the guidance of Dr. Ishan Thakkar. My doctoral research focused on the cross-layer design and optimization of photonic integrated-circuit-based AI accelerators.

Portrait of Sairam Sri Vatsavai

News

Sept 2026

Three workshop papers accepted at SC 26 in Ai4S, AionHPC and PMBS workshops

  • LightshowAI-Agent: An MCP-Based Agentic Framework for Real-Time and Reproducible X-Ray Absorption Spectral Analysis at Scientific User Facilities
  • HOLOS: A Gradient-Descent-Based Design-Space Exploration Framework for Hierarchical AI Accelerator Systems
  • DMSim: Configurable Data Management Simulation Framework for Scientific Computing Grid

Aug 2026

Delivered a lightning talk and presented a poster at ModSim 2026, Seattle, WA

Presented “AI-Enabled ModSim for Distributed Computing: A Simulator-to-Surrogate Methodology for Scalable Performance Modeling.”

July 2026

Paper accepted at IEEE eScience 2026, Naples, Italy

“CGSim: A Simulation Framework for Large Scale Distributed Computing Infrastructures with AI-Driven Applications” was accepted to the 22nd IEEE International Conference on eScience, to be held September 28 to October 2, 2026.

Jul 2026

Presented a talk and poster on the REDWOOD project at the ASCR Computer Science PI Meeting, on behalf of Alexei Klimentov

Presented progress updates and future directions for the REDWOOD project.

Jul 2026

Delivered a plenary talk at ATLAS Software and Computing Week, CERN, Geneva, Switzerland

Presented “Resilient Federated Workflows in a Heterogeneous Computing Environment: The REDWOOD Project.”

Jun 2026

Delivered a talk and served as a panelist at a mini-symposium during PASC 2026, University of Bern, Switzerland

Presented “AI-Enabled Modeling, Simulation, and Optimization of Distributed Computing Systems.”

May 2026

Live demonstration of AmSC-enabled LightshowAI at Confab26, Rockville, MD

Demonstrated real-time X-ray absorption spectroscopy analysis using AmSC-enabled LightshowAI, presented under the theme of AI-enabled scientific discovery. Our Demo is featured on AmSC website here.

May 2026

Invited talk at Optics-Laser 2026, 4th Innovations in Optics, Photonics, and Laser Engineering Conference, Boston, MA

Delivered an invited talk titled “Cross-Layer Design of Highly Scalable and Energy-Efficient AI Accelerator Systems Using Photonic Integrated Circuits” on 18 to 19 May 2026.

May 2026

Promoted to Research Staff 3/Assistant Computational Scientist, at Brookhaven National Laboratory

Transitioned from Postdoctoral Research Associate to a research staff appointment in the Computing and Data Sciences Department, within the Systems, Architectures, and Advanced Technologies group.

Research

Two connected threads: modeling complex computing systems, and designing alternative hardware for AI.

Modeling and surrogates for distributed computing

Discrete-event simulators reproduce the behavior of production grids, and learned surrogates stand in for them once a search needs thousands of rollouts. The goal is scheduling-policy search at facilities where a single real experiment costs weeks of grid time.

Photonic and beyond-CMOS accelerators

Microring and interferometric meshes can carry many computations at once across wavelength, time, spatial mode, and polarization. My work spans the device models, the mapping from workload to degrees of freedom, and the benchmarking that decides whether any of it beats a GPU.

Publications

Selected peer-reviewed work, followed by manuscripts currently under review or in preparation.

2026

Predicting job turnaround time in large-scale distributed computing environments with graph neural networks

EPJ Research Infrastructures, volume 10, article 14  Paper

2025

CGSim, a SimGrid-based discrete-event simulator for distributed scientific computing Best short paper

PMBS Workshop at SC 2025  Paper

2025

HEANA, a hybrid time-amplitude analog optical accelerator with flexible dataflows for energy-efficient CNN inference

ACM Transactions on Design Automation of Electronic Systems, volume 30, issue 2  Paper

2023

SCONNA, a stochastic computing based optical accelerator for ultra-fast, energy-efficient inference of integer-quantized CNNs

IEEE International Parallel and Distributed Processing Symposium  Paper

2022

Photonic reconfigurable accelerators for efficient inference of CNNs with mixed-sized tensors

IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, volume 41, issue 11  Paper

2020

PROTEUS, rule-based self-adaptation in photonic NoCs for loss-aware co-management of laser power and performance

IEEE/ACM International Symposium on Networks-on-Chip  Paper

Under review and in preparation

Projects

Current research efforts spanning scientific infrastructure, photonic computing, X-ray science, and system co-design.

REDWOOD

A DOE ASCR project on modeling and optimizing scientific cyberinfrastructure. I build the simulation and surrogate stack, CGSim and TRASSE, and the training pipelines that cover 74 WLCG sites.

COSMOS

A Brookhaven LDRD on simulation-driven co-design of multidimensional photonic computing systems. I am a co-investigator leading benchmarking and evaluation against GPU, TPU, and single-degree-of-freedom photonic baselines.

LightshowAI

An X-ray absorption spectroscopy platform for NSLS-II. I work on federated authentication, streaming beamline data, and the agentic layer that exposes surrogate models and materials databases as tools.

HOLOS

A gradient-descent design space exploration framework that searches parallelism strategy and accelerator geometry together, across CMOS and superconducting digital technologies.

Service

Reviewing activity separated by journals and conferences for faster scanning.

Journals
  • IEEE Transactions on Computers
  • IEEE Transactions on Computer-Aided Design
Conferences
  • SC 2025
  • VLSI Design
  • Great Lakes Symposium on VLSI

Talks

Selected recent presentations, separated from professional service.

2026

Simulator-to-surrogate performance modeling for distributed computing

PASC 2026 · Bern

2026

Grid simulation and surrogates for ATLAS

ATLAS Software and Computing Week · Plenary

2026

AI-enabled ModSim for distributed computing

ModSim 2026