DLS 2020
Sun 15 - Fri 20 November 2020 Online Conference
co-located with SPLASH 2020
Thu 19 Nov 2020 12:00 - 12:20 at SPLASH-III - 7 Chair(s): Kedar Namjoshi, Tim Felgentreff
Fri 20 Nov 2020 00:00 - 00:20 at SPLASH-III - 7 Chair(s): Mihaela Sighireanu

To efficiently execute dynamically typed languages, many language implementations have adopted a two-tier architecture. The first tier aims for low-latency startup times and collects dynamic profiles, such as the dynamic types of variables. The second tier provides high-throughput using an optimizing compiler that specializes code to the recorded type information. If the program behavior changes to the point that not previously seen types occur in specialized code, that specialized code becomes invalid, it is deoptimized, and control is transferred back to the first tier execution engine which will start specializing anew. However, if the program behavior becomes more specific, for instance, if a polymorphic variable becomes monomorphic, nothing changes. Once the program is running optimized code, there are no means to notice that an opportunity for optimization has been missed.

We propose to employ a sampling-based profiler to monitor native code without any instrumentation. The absence of instrumentation means that when the profiler is not active, no overhead is incurred. We present an implementation is in the context of the \v{R} just-in-time, optimizing compiler for the R language. Based on the sampled profiles, we are able to detect when the native code produced by \v{R} is specialized for stale type feedback and recompile it to more type-specific code. We show that sampling adds an overhead of less than 3% in most cases and up to 9% in few cases and that it reliably detects stale type feedback within milliseconds.

Conference Day
Thu 19 Nov

Displayed time zone: Central Time (US & Canada) change

11:00 - 12:20
7SAS / DLS 2020 at SPLASH-III +12h
Chair(s): Kedar NamjoshiNokia Bell Labs, Tim FelgentreffOracle Labs, Potsdam
11:00
20m
Research paper
Interprocedural Shape Analysis Using Separation Logic-based Transformer Summaries
SAS
Hugo IllousCEA & INRIA / ENS Paris, Matthieu LemerreCEA LIST, France, Xavier RivalINRIA/CNRS/ENS Paris
File Attached
11:20
20m
Talk
DelayRepay: Delayed Execution for Kernel Fusion in Python
DLS 2020
John Magnus MortonUniversity of Edinburgh, Kuba KaszykUniversity of Edinburgh, Lu LiLinköping University, Jiawen SunUniversity of Edinburgh, Christophe DubachMcGill University, Michel SteuwerThe University of Edinburgh, Murray ColeUniversity of Edinburgh, UK, Michael F. P. O'BoyleUniversity of Edinburgh
Link to publication DOI Pre-print Media Attached
11:40
20m
Research paper
Stratified Guarded First-order Transition Systems
SAS
Christian MüllerTechnische Universität München, Saarland University, Helmut SeidlTechnische Universität München
File Attached
12:00
20m
Talk
Sampling Optimized Code for Type Feedback
DLS 2020
Olivier FlückigerNortheastern University, Andreas WälchliUniversity of Bern, Sebastián KrynskiCzech Technical University, National University of Quilmes, Jan VitekNortheastern University / Czech Technical University
Link to publication DOI Pre-print Media Attached
23:00 - 00:20
7DLS 2020 / SAS at SPLASH-III
Chair(s): Mihaela SighireanuLSV, ENS Paris-Saclay
23:00
20m
Research paper
Interprocedural Shape Analysis Using Separation Logic-based Transformer Summaries
SAS
Hugo IllousCEA & INRIA / ENS Paris, Matthieu LemerreCEA LIST, France, Xavier RivalINRIA/CNRS/ENS Paris
File Attached
23:20
20m
Talk
DelayRepay: Delayed Execution for Kernel Fusion in Python
DLS 2020
John Magnus MortonUniversity of Edinburgh, Kuba KaszykUniversity of Edinburgh, Lu LiLinköping University, Jiawen SunUniversity of Edinburgh, Christophe DubachMcGill University, Michel SteuwerThe University of Edinburgh, Murray ColeUniversity of Edinburgh, UK, Michael F. P. O'BoyleUniversity of Edinburgh
Link to publication DOI Pre-print Media Attached
23:40
20m
Research paper
Stratified Guarded First-order Transition Systems
SAS
Christian MüllerTechnische Universität München, Saarland University, Helmut SeidlTechnische Universität München
File Attached
00:00
20m
Talk
Sampling Optimized Code for Type Feedback
DLS 2020
Olivier FlückigerNortheastern University, Andreas WälchliUniversity of Bern, Sebastián KrynskiCzech Technical University, National University of Quilmes, Jan VitekNortheastern University / Czech Technical University
Link to publication DOI Pre-print Media Attached