Early Career Lighting Talks - Balancing Particle GPU Memory Constraints in Nyx Cosmology Code
Event Type
Workshop
Online Only
Career Development
Diversity Equity Inclusion (DEI)
Education and Training and Outreach
HPC Community Collaboration
W
TimeSunday, 14 November 20213:55pm - 4pm CST
LocationOnline
DescriptionThe Nyx cosmology code is used to simulate the formation of large scale structure in Lyman-alpha simulations of the universe. As the dark matter particles begin clustering, the cost of a single time step grows due to the load imbalance. In particular, the Poisson solve for computing self-gravity becomes more expensive when there are highly clustered regions in the domain. These highly clustered regions can also prohibit fitting the entire problem in GPU HBM. If the entire problem does not fit on the HBM, Nyx should use managed memory, and the cost of each time step becomes dependent on the host-device memory bandwidth. In this talk, we will focus on the effect of load imbalance on the GPU memory, as well as the current approach in Nyx to remedying this.