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Sun 23 Jun 2019 09:05 - 09:45 at 106A - Scaling Up

Modern programs, and especially low-level libraries, often rely on concurrent memory accesses that do not enforce memory ordering, such as C++’s memory_order_relaxed accesses. Concurrent garbage collectors commonly rely on such accesses, as does a surprising amount of other performance-critical software. On some common architectures, it is both unnecessary and quite expensive to guarantee ordering for these accesses.

Unfortunately, we still have no agreement on an acceptable semantics for such accesses. Hence verification of algorithms like realistic concurrent garbage collectors appears infeasible. We review the so-called “out-of-thin-air” problem, the technical obstacles, and the ongoing controversy surrounding performance of a possible solution. We focus on some examples to illustrate that existing implementations may in fact produce extremely surprising results for code that includes unordered memory accesses.

Sun 23 Jun

Displayed time zone: Tijuana, Baja California change

09:00 - 11:00
Scaling UpISMM 2019 at 106A
09:00
5m
Day opening
Welcome from the chairs
ISMM 2019
Harry Xu University of California, Los Angeles (UCLA), Jeremy Singer University of Glasgow
09:05
40m
Talk
Keynote 1: Relaxed memory ordering needs a better specification
ISMM 2019
09:45
25m
Talk
Automatic GPU Memory Management for Large Neural Models in TensorFlow
ISMM 2019
Tung D. Le IBM Research - Tokyo, Haruki Imai IBM Research - Tokyo, Yasushi Negishi IBM Research - Tokyo, Kiyokuni Kawachiya IBM Research - Tokyo
10:10
25m
Talk
Massively Parallel GPU Memory Compaction
ISMM 2019
Matthias Springer Tokyo Institute of Technology, Hidehiko Masuhara Tokyo Institute of Technology
10:35
25m
Talk
Scaling Up Parallel GC Work-Stealing in Many-Core Environments
ISMM 2019
Michihiro Horie IBM Research - Tokyo, Kazunori Ogata IBM Research, Japan, Mikio Takeuchi IBM Research - Tokyo, Hiroshi Horii IBM Research, Japan