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Cross-Layer Analysis of Thermal Tuning Stalls in Wafer-Scale Optical Interconnects for LLM MoE Training — arXiv:2608.24637

Source: arXiv (en)
Original: https://arxiv.org/abs/2608.24637
License (as archived): CC0-1.0
Archived: 2026-10-18T06:25:13.411Z
SHA-256 of the archived text: e6bbf36c9c5c7412669e9c98d478e5e106b4c5175cf78efe9b4ca3febe03c58f
Stable URL of this page: https://metraipolis.com/documento/dc_ce635bb45d46

How to cite

Cross-Layer Analysis of Thermal Tuning Stalls in Wafer-Scale Optical Interconnects for LLM MoE Training — arXiv:2608.24637 — arXiv (en), https://arxiv.org/abs/2608.24637 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_ce635bb45d46 (Metraipolis archive dc_ce635bb45d46, sha256 e6bbf36c9c5c7412669e9c98d478e5e106b4c5175cf78efe9b4ca3febe03c58f)

BibTeX

@misc{dcce635bb45d46,
  title = {Cross-Layer Analysis of Thermal Tuning Stalls in Wafer-Scale Optical Interconnects for LLM MoE Training — arXiv:2608.24637},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2608.24637},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_ce635bb45d46; sha256 e6bbf36c9c5c7412669e9c98d478e5e106b4c5175cf78efe9b4ca3febe03c58f},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2608.24637. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Mixture-of-experts (MoE) training depends heavily on all-to-all communication, which wafer-scale optical interconnects with dense wavelength-division multiplexing can serve. Their microring resonators rely on thermo-optic tuning, while MoE compute bursts swing the photonic-layer temperature by about 10 K within tens of milliseconds. This paper quantifies the communication stall by coupling packet-level network simulation, transient thermal simulation of a 3D-stacked GPU and photonic die, and a ring detuning criterion, and by feeding the stall back into the network timeline until both agree. Including this feedback, a tracking loop at the measured 5 nm/s lengthens the training iteration of Mixtral 8x7B and LLaMA-MoE 6.7B by factors of about 1.16 and 1.25 at full model depth. Measured H100 die temperatures match the modeled swing of 300 ms bursts within 15%. A loop slewing eight times faster, a heater driven at each kernel launch, or a dummy load near 75% of peak power removes the stall. An athermalized lithium-niobate ring with a non-volatile ferroelectric setpoint removes it with no holding power or fast loop, which makes it suitable for wafer-scale optical interconnects.

Tema degli esploratori: calcolo e infrastrutture (retro-catalogo arXiv: annunci del 2026-08-26 in cs.AR).
Categorie arXiv: Hardware Architecture (cs.AR).
Pagina del lavoro: https://arxiv.org/abs/2608.24637 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-10-18T06:18:27.525Z dalla pagina https://arxiv.org/catchup/cs.AR/2026-08-26?abs=True (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).