Shows that I/O time, bandwidth, and IOPS each expose different bottlenecks in HACC, Montage, and CM1.
Abstract
HPC systems, driven by the rise of workloads with significant data requirements, face challenges in I/O performance. To address this, a thorough I/O analysis is crucial to identify potential bottlenecks. However, the multitude of metrics makes it difficult to pinpoint the causes of low I/O performance. In this work, we analyze three scientific workloads using three widely accepted I/O metrics. We demonstrate that different metrics uncover different I/O bottlenecks, highlighting the importance of considering multiple metrics for comprehensive I/O analysis.
@misc{yildirim2023exploringimpacts,
title = {{Exploring the Impacts of Multiple I/O Metrics in Identifying I/O Bottlenecks}},
author = {Yildirim, Izzet and Devarajan, Hariharan and Kougkas, Anthony and Sun, Xian-He and Mohror, Kathryn},
howpublished = {Research poster, SC '23: International Conference for High Performance Computing, Networking, Storage, and Analysis},
year = {2023},
month = nov,
url = {https://sc23.supercomputing.org/proceedings/tech_poster/tech_poster_pages/rpost163.html},
}
AgentStage: Exploiting LLM Thinking for Data Staging in Scientific Agents
eScience ’26 · Conference paper · First author
optimize
Uses an agent’s thinking time to stage data from cold storage into a tiered node-local cache (memory, then NVMe) before the agent asks for it.
A Multifaceted Approach to Automated I/O Bottleneck Detection for HPC Workloads
SC ’22 · Poster · First author
diagnose
DigIO, a tool that finds I/O bottlenecks automatically from a multifaceted view of a workload’s traces; the precursor to WisIO.
Correct Is Not I/O Efficient: Characterizing I/O Behavior of LLM Agents on Scientific Data
GCASR ’26 · Poster · First author
observe
Characterizes the I/O behavior of LLM agents working on scientific data: an agent can reach a correct answer while doing far more I/O than the task needs.
DFTracer: An Analysis-Friendly Data Flow Tracer for AI-Driven Workflows
SC ’24 · Conference paper · Co-author
observe
An analysis-friendly data-flow tracer for AI-driven workflows, developed at LLNL.
GDSight: Per-Operation Cross-Layer Attribution for GPUDirect Storage
PDSW ’26, at SC ’26 (accepted) · Workshop paper · First author
observe+analyze
Per-operation, cross-layer attribution for GPUDirect Storage: where a single GPU read spends its time, from the application down to the device.
Exploring the Impacts of Multiple I/O Metrics in Identifying I/O Bottlenecks
SC ’23 · Poster · First author
diagnose
Shows that I/O time, bandwidth, and IOPS each expose different bottlenecks in HACC, Montage, and CM1.
IOMax: Maximizing Out-of-Core I/O Analysis Performance on HPC Systems
PDSW ’23, at SC ’23 · Workshop paper · First author
analyze
Makes out-of-core analysis of very large I/O traces fast on HPC systems.
Performance Analysis of Containerized OrangeFS in HPC Environment
SC ’21 · Poster · First author
analyze
Compares five container runtimes hosting the OrangeFS parallel file system; Singularity came closest to bare metal.
ORION: Observability Framework for Hybrid Workflow-Centric I/O Monitoring in HPC Systems
ProTools ’26, at SC ’26 (accepted) · Workshop paper · Co-author
observe
An observability framework for hybrid, workflow-centric I/O monitoring on HPC systems. I co-authored it.
Optimizing I/O for an Exascale Implicit Kinetic Plasma Simulation using the Rabbit Storage System
REX-IO ’25, at IEEE Cluster ’25 · Workshop paper · Co-author
optimize
I/O optimization for an exascale implicit kinetic plasma simulation on LLNL’s Rabbit near-node NVMe storage.
Recorder: Comprehensive Parallel I/O Tracing and Analysis
Preprint, under review · Journal paper · Co-author
observe
Comprehensive parallel I/O tracing and analysis across HPC I/O libraries.
StageOnce: Speculative Cross-Job Data Staging for LLM Agent Fleets
SC ’26 (accepted) · Poster · First author
optimize
Speculative cross-job data staging for fleets of LLM agents.
ToolFuse: Provenance-Aware In-Flight Coalescing of Redundant Agent Tool Calls
SC ’26 (accepted) · Poster · First author
optimize
Provenance-aware, in-flight coalescing of redundant agent tool calls.
WisIO: Automated I/O Bottleneck Detection with Multi-Perspective Views for HPC Workflows
ICS ’25 · Conference paper · First author
analyze+diagnose
Automated I/O bottleneck detection for HPC workflows, using correlated views of the same trace from several perspectives.