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Eidola: Modeling Multi-GPU Network Communication Traffic in Distributed AI Workloads

Ranganath R. Selagamsetty, Matthew Poremba, Bradford M. Beckmann, Joshua San Miguel 2026-06-14
Gem5 × Interconnect Microarchitecture Simulation HPC Compiler Runtime GPU

Eidola addresses the problem of modeling irregular and transient inter-GPU communication traffic in distributed AI workloads, which existing tools fail to capture due to fine-grained synchronization and peer-to-peer writes. The method introduces a scalable gem5 extension that uses annotated timing profiles from real applications to emulate peer-to-peer GPU writes with cycle-level precision. Experimental evidence demonstrates Eidola's effectiveness by reproducing variability in fused kernel execution and confirming reductions in polling-related memory traffic via a SyncMon-inspired mechanism. This matters because Eidola provides a flexible platform for architectural exploration of interconnect bandwidth and latency in modern multi-GPU systems.

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Partitioned Tags, Shared Data: Reconciling Strict Cache Isolation with Write-Shared Coherence

Kartik Ramkrishnan, Stephen McCamant, Antonia Zhai, Pen Chung Yew 2026-06-14
Gem5 × Microarchitecture Simulation Cache

SCP solves the problem that write-shared coherence fails under strict cache partitioning, a decade-old barrier to deploying eviction-based side-channel defenses in secure shared-OS settings. The method partitions only the tags while sharing a single data pool, sizes the data pool to prevent capacity-driven cross-partition eviction, and routes writes to the LLC after a leakage threshold to mitigate coherence-based leakage. Experimental evidence from gem5 shows SCP mitigates Prime+Probe, Flush+Reload, and shared-writeable-line attacks to no better than random guessing, with a +2.8% LLC SRAM hardware cost and IPC within 0.3% of DAWG on SPEC CPU2017. This matters because SCP reconciles strict cache isolation with write-shared coherence, enabling secure partitioning without sacrificing performance or coherence correctness.

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