With ubiquitous multicore processors and the increasing role of hardware accelerators, polyhedral compilation techniques have gained a lot of attention in both academia and industry. Polyhedral compilation provides a homogeneous framework to design effective optimizations for high performance computing, addressing coarse-grain and fine-grain parallelism, distributed- and shared-memory parallelism. IMPACT is a unique workshop focusing exclusively on polyhedral compilation technologies, bringing together researchers and practitioners for a high-quality one-day event including technical paper presentations and panel discussions. This is the fifth edition of IMPACT and is being organized in conjunction with with HiPEAC 2015 in Amsterdam, The Netherlands as a full-day workshop.

We welcome both theoretical and experimental papers on all aspects of polyhedral compilation and optimization. We also welcome submissions describing preliminary results, crazy new ideas, position papers, experience reports, and available tools, with an aim to stimulate discussions, collaborations, and advances in the field. Topics of interest include, but are not limited to:

• program optimization (automatic parallelization, tiling, etc.)
• code generation
• data/communication management on GPUs, accelerators and distributed systems
• hardware/high-level synthesis for affine programs
• static analysis
• program verification
• model checking
• theoretical foundations of the polyhedral model
• extensions of the polyhedral model
• scalability and robustness of polyhedral compilation techniques
• tool demonstration

Submissions

Submissions should not exceed 8 pages (recommended 6 pages) formatted as per ACM proceedings format. When preparing your manuscript, please use the "Tighter Alternate style" available from http://www.acm.org/sigs/publications/proceedings-templates .
Submissions should be in PDF format and printable on US letter or A4 sized paper. Please send your submission by the (extended) deadline to:
impact-chairs@lists.gforge.inria.fr
Please indicate in your email if you wish to submit as a:

• regular paper
• position paper
• wild and crazy idea
• tool demonstration

Proceedings will be published online. If the final version of an accepted paper does not sufficiently address the comments of the reviewers, then it may be accompanied by a note from the program committee. Publication at IMPACT will not prevent later publication in conferences or journals of the presented work.

Important Dates

Abstract submission:	October 17, 2014
Submission deadline:	October 24, 2014
Notification of decision:	November 22, 2014
Final version due:	December 8, 2014 (extended to Dec. 15)
Workshop:	January 19, 2014

Program

Session I: Reductions and array reconstructions (10:00 - 11:10)

Session Chair: Armin Grösslinger



• Welcome
  Alexandra Jimborean
  [slides]
  


• On recovering multi-dimensional arrays in Polly
  Tobias Grosser, Sebastian Pop, J. Ramanujam, P. Sadayappan
  [paper] [slides]
  


• Polly's polyhedral scheduling in the presence of reductions
  Johannes Doerfert, Kevin Streit, Sebastian Hack, Zino Benaissa
  [paper] [slides]
  



Break (11:10 - 11:30)



Session II: Optimizations for performance (11:30 - 13:00)

Session Chair: Louis-Noël Pouchet



• CPU+GPU load balance guided by execution time prediction
  Jean-François Dollinger, Vincent Loechner
  [paper] [slides]
  


• Automatic tiling of "mostly-tileable" loop nests
  David Wonnacott, Tian Jin, Allison Lake
  [paper] [slides]
  


• Mind the gap! A study of some pitfalls preventing peak performance in polyhedral compilation using a polyhedral antidote
  Philippe Clauss
  [paper] [slides]
  



Lunch (13:00 - 14:00)



Session III: Expanding and extending polyhedral techniques (15:00 - 16:30)

Session Chair: David G. Wonnacott



• Polyhedral transformations of explicitly parallel programs
  Prasanth Chatarasi, Jun Shirako, Vivek Sarkar
  [paper] [slides]
  


• The power of polynomials
  Paul Feautrier
  [paper] [slides]
  


• Integer set coalescing
  Sven Verdoolaege
  [paper] [slides]
  



Break (16:30 - 17:00)



Session IV: Polyhedral-related tools and poster teasers (17:00 - 17:45)

Session Chair: Tomofumi Yuki



• Manipulating visualization, not codes
  Oleksandr Zinenko, Stéphane Huot, Cédric Bastoul
  [paper] [slides]
  

Poster teasers:


• Compiler/runtime framework for dynamic dataflow parallelization of tiled programs
  Martin Kong, Antoniu Pop, R. Govindarajan, Louis-Noël Pouchet, Albert Cohen, P. Sadayappan
  [poster] [slides]
  


• Towards automated characterization of the data movement complexity of affine programs
  Venmugil Elango, Fabrice Rastello, Louis-Noel Pouchet, J. Ramanujam, P. Sadayappan
  [poster] [slides]
  


• Task coarsening through polyhedral compilation for a macro-dataflow programming model
  Alina Sbirlea, Louis-Noël Pouchet, Vivek Sarkar
  [poster] [slides]
  


• Parallelizing Stencils Automatically for Energy
  Yun Zou, Sanjay Rajopadhye
  


• Influence of array storage and access methods on performance of multi-dimensional arrays used in programs with high cache reuse
  Tian Jin, David G. Wonnacott
  [poster] [slides]
  


• On recovering multi-dimensional arrays in Polly
  Tobias Grosser, Sebastian Pop, J. Ramanujam, P. Sadayappan
  


Concluding remarks and discussions (17:45 - 18:00)


• Wrap-up and discussions on the reviewing process and dissemination
  Alain Darte
  [slides]

Location

The workshop is organized in conjunction with HiPEAC 2015 and will take place in room E104 of the Forum Centre at Amsterdam RAI .

Contact us

Please send any questions or comments to Alain Darte and Alexandra Jimborean: impact-chairs@lists.gforge.inria.fr.