Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · hep-lat/9509003

Performance of the Cray T3D and Emerging Architectures on Canopy QCD Applications

Mark Fischler·Mike Uchima
View original source ↗Read source document ↗Export metadata ↓

Abstract

The Cray T3D, an MIMD system with NUMA shared memory capabilities and in principle very low communications latency, can support the Canopy framework for grid-oriented applications. CANOPY has been ported to the T3D, with the intent of making it available to a spectrum of users. The performance of the T3D running Canopy has been benchmarked on five QCD applications extensively run on ACPMAPS at Fermilab, requiring a variety of data access patterns. The net performance and scaling behavior reveals an efficiency relative to peak Gflops almost identical to that achieved on ACPMAPS. Detailed studies of the major factors impacting performance are presented. Generalizations applying this analysis to the newly emerging crop of commercial systems reveal where their limitations will lie. On these applications, efficiencies of above 25\% are not to be expected; eliminating overheads due to Canopy will improve matters, but by less than a factor of two.

Explore related subjects

hep-lat

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Mark Fischler, Mike Uchima. 1995-09-01. Performance of the Cray T3D and Emerging Architectures on Canopy QCD Applications. https://doi.org/10.1016/0920-5632(96)00180-6

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

A Machine Learning study of the two-dimensional antiferromagnetic $Q$-state Potts model on the square lattice

The critical phenomena of 2D antiferromagnetic $Q$-state Potts model on the square lattice with $Q=2,3,4,5$ and 6 are investigated using supervised neural networks (NN). Conventional supervised and unsupervised NNs either fail or have difficulty in identifying the correct critical behaviors of these models. Remarkably, despite the fact that the NNs employed here are trained with a particular fixed type training set which contains no information about the considered models (except for $Q=2$), they correctly compute the critical temperatures for the studied physical systems. Particularly, the NN outcomes suggest convincingly that the $Q=3$ model is critical only at zero temperature and $Q=4,5,6$ models remain disordered at all temperatures. Apart from the studied models, our NNs trained with exactly the same training set have successfully determined the critical temperature(s) and the nature of the associated phase transition(s) of another physical system differing dramatically from those considered here. Therefore, our NN has the potential to be a universally applicable NN model in studying phase transitions.

hep-lat↗
arXiv2026

Chiral Response of QCD Topology across the Thermal Crossover

We introduce a novel relation connecting the light-quark-mass derivative of the topological susceptibility in quantum chromodynamics (QCD) to the connected correlation between the squared topological charge and the integrated light-quark scalar density. This relation gives direct access to the chiral response of QCD topology---the local logarithmic light-quark-mass derivative of the susceptibility---from a single ensemble at fixed quark masses for each temperature, without additional simulations at shifted masses. Applying this relation to $(2+1)$-flavor lattice QCD at $m_π\simeq220\,\mathrm{MeV}$ over temperatures ranging from well below to well above the chiral crossover, we find that the response rises rapidly through the crossover from approximately unity toward two. This evolution corresponds to a change from nearly linear to nearly quadratic dependence of the topological susceptibility on the light-quark mass. Using the chiral response as the exponent of a local power law in the light-quark mass, we determine its effective amplitude from the topological susceptibility. This amplitude exhibits a maximum near the crossover temperature, reflecting the competition between the decreasing topological susceptibility and the increasing chiral response. These results reveal a thermal reorganization of the quark-mass dependence of QCD topology beyond the suppression of topological fluctuations alone.

hep-lat↗
arXiv2026

Toward Compute-Bound Lattice-QCD Software

Multi-right-hand-side multigrid inverters for lattice QCD are much less memory constrained than single-right-hand-side Krylov solvers, so the upper bound on efficiency of modern solvers is much higher than what was historically possible. This work presents a reanalysis of roofline estimates to reflect this new reality. It also describes the qc library, which implements multi-right-hand-side multigrid at an efficiency that can exceed 50% of the processor roofline.

hep-lat↗