Tyler Sorensen
Tyler Sorensen

Tyler Sorensen

PhD student at Imperial College London
Department of computer science in the Multicore Programming Group
t (dot) sorensen15 (AT) imperial.ac.uk


Paper about GPU scheduling guarantees accepted to CONCUR 2018!
PLDI'18 paper won a distinguished paper award!
Paper about transactional memory under weak memory models accepted to PLDI'18!


I am a PhD student (started Fall 2014) in the multicore programming group at Imperial supervised by Alastair Donaldson.

I study testing and modeling of GPU programming with an emphasis fine grained communication idioms.

Below is a .gif showing the magnitude of weak memory consistency behaviours for three litmus tests (MP, SB, LB) that appear when stressing individual memory locations of a scratchpad location. These patterns were key in finding and observing weak memory bugs in GPU applications (explained in PLDI'16 paper)

Here's a video that I made (with Jade Alglave) showing a visualization and explanation of one of the GPU memory model bugs we found (documented in ASPLOS'15 paper).

Publications (conference):

GPU schedulers: how fair is fair enough? with: Hugues Evrard, and Alastair F. Donaldson. (CONCUR 2018)

The Semantics of Transactions and Weak Memory in x86, Power, ARM, and C++ lead authors: Nathan Chong and John Wickerson (PLDI 2018)
Distinguished paper award

Cooperative Kernels: GPU Multitasking for Blocking Algorithms with: Hugues Evrard, and Alastair F. Donaldson. (FSE 2017) [poster] [slides]
Distinguished paper award
Model contributed to the model checking comptition based on the resizing barrier in this work (by Hugues). See here

Automatically Comparing Memory Consistency Models lead author: John Wickerson , with: Mark Batty and George A. Constantinides (POPL 2017)

Portable Inter-Workgroup Barrier Synchronisation for GPUs with: Alastair F. Donaldson, Mark Batty, Ganesh Gopalakrishnan, and Zvonimir Rakamaric. (OOPSLA 2016) [code][slides]

Exposing Errors Related to Weak Memory in GPU Applications with: Alastair F. Donaldson. (PLDI 2016) [slides][talk]

GPU Concurrency: Weak Behaviours and Programming Assumptions with: Jade Alglave, Mark Batty, Alastair F. Donaldson, Ganesh Gopalakrishnan, Jeroen Ketema, Daniel Poetzl, and John Wickerson. (ASPLOS 2015) [poster] [project page]

Publications (peer-reviewed workshops):

The Hitchhiker's Guide to Cross-Platform OpenCL Application Development with: Alastair F. Donaldson. (IWOCL 2016) [slides]

I compute, therefore I am (buggy): methodic doubt meets multiprocessors with: Jade Alglave, Luc Maranget, and Daniel Poetzl. (TinyToCS 2015) [project page]

Towards Shared Memory Consistency for GPUs with: Jade Alglave, Ganesh Gopalakrishnan and Vinod Grover. (ICS 2013 poster) (undergraduate ACM SRC 2014 paper) [poster] [paper]
1st place prize in undergraduate ICS ACM poster competition

Some projects

Imperial Art of Research Competition - Helped generate several interesting images relating to GPU correctness issues
Won a staff pick award

DIY Memory Model Tools - Contributed GPU features to Litmus (hardware testing) and Herd (memory model simulating)
Contributions mentioned in LWN article

Python BDD Package and Web Interface - Main developer and maintainer


Testing and Exposing Weak GPU Memory Models - MS thesis University of Utah 2014
Confirmed and repaired CUDA by Example bug (errata)

Towards Shared Memory Consistency for GPUs - Undergraduate thesis University of Utah 2013


Awards and recognition: