Skip to content

Stalls on Ampere #22

Open
Open

Description

@govertb

Running on a GeForce RTX 3090 (Ampere architecture) the code stalls in the SortKernel. Possibly because certain threads no longer co-reside on the same multiprocessor during shared memory reductions in the SummarizationKernel and/or SortKernel.

Activity

  1. hubbardp commented on Aug 3, 2024

    @hubbardp

    I think I am encountering this problem, too, on a A6000. If I comment out the call to SortKernel then the code finishes all the iterations without stalling. This bug is a shame, because the performance seems very good.

  2. govertb commented on Oct 26, 2024

    @govertb
    OwnerAuthor

    From the paper on this project, I see we used CUDA 7.5 at the time. I checked the corresponding docs ('CUDA Compiler Driver NVCC' ) and in CUDA 7.5 nvcc defaults to compiling with

    --gpu-architecture=compute_20 --gpu-code=sm_20,compute_20
    

    In recent versions of CUDA nvcc defaults to compiling with

    --gpu-architecture=compute_52 --gpu-code=sm_52,compute_52
    

    Explicitly targeting a 'virtual architecture' (e.g. explicitly passing the CUDA 7.5 defaults) would fix some things. I'm curious if it would resolve the stalling, unfortunately don't have access to an Ampere GPU any more. But even if it resolves the stalling, breaking changes between CUDA 7.5 and recent versions need to be addressed as well.

    Edit: I see support for Compute Capability 2.0 was dropped starting with CUDA 9.0.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions