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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

ismm-2019-papers
09:00 - 11:00: ISMM 2019 - Scaling Up at 106A
ismm-2019-papers09:00 - 09:05
Day opening
Harry XuUniversity of California, Los Angeles (UCLA), Jeremy SingerUniversity of Glasgow
ismm-2019-papers09:05 - 09:45
Talk
ismm-2019-papers09:45 - 10:10
Talk
Tung D. LeIBM Research - Tokyo, Haruki ImaiIBM Research - Tokyo, Yasushi NegishiIBM Research - Tokyo, Kiyokuni KawachiyaIBM Research - Tokyo
ismm-2019-papers10:10 - 10:35
Talk
Matthias SpringerTokyo Institute of Technology, Hidehiko MasuharaTokyo Institute of Technology
ismm-2019-papers10:35 - 11:00
Talk
Michihiro HorieIBM Research - Tokyo, Kazunori OgataIBM Research, Japan, Mikio TakeuchiIBM Research - Tokyo, Hiroshi HoriiIBM Research, Japan