Wed 17 Jun 2015 10:05 - 10:30 at PLDI Main BLUE (Portland 254-255) - Performance Chair(s): Mary Hall

Highly optimized programs are prone to bit rot, where performance quickly becomes suboptimal in the face of new hardware and compiler techniques. In this paper we show how to automatically lift performance-critical stencil kernels from a stripped x86 binary and generate the corresponding code in the high-level domain-specific language Halide. Using Halide’s state-of-the-art optimizations targeting current hardware, we show that new optimized versions of these kernels can replace the originals to rejuvenate the application for newer hardware.

The original optimized code for kernels in stripped binaries is nearly impossible to analyze statically. Instead, we rely on dynamic traces to regenerate the kernels. We perform buffer structure reconstruction to identify input, intermediate and output buffer shapes. We abstract from a forest of concrete dependency trees which contain absolute memory addresses to symbolic trees suitable for high-level code generation. This is done by canonicalizing trees, clustering them based on structure, inferring higher-dimensional buffer accesses and finally by solving a set of linear equations based on buffer accesses to lift them up to simple, high-level expressions.

Helium can handle highly optimized, complex stencil kernels with input-dependent conditionals. We lift seven kernels from Adobe Photoshop giving a 75% performance improvement, four kernels from IrfanView, leading to 4.97× performance, and one stencil from the miniGMG multigrid benchmark netting a 4.25× improvement in performance. We manually rejuvenated Photoshop by replacing eleven of Photoshop’s filters with our lifted implementations, giving 1.12× speedup without affecting the user experience.

Wed 17 Jun

pldi2015-papers
09:15 - 10:55: Research Papers - Performance at PLDI Main BLUE (Portland 254-255)
Chair(s): Mary HallUniversity of Utah
pldi2015-papers09:15 - 09:40
Talk
Oswaldo Olivo, Isil DilligUniversity of Texas, Austin, Calvin LinUT Austin
Media Attached
pldi2015-papers09:40 - 10:05
Talk
Yufei DingNorth Carolina State University, Jason AnselMassachusetts Institute of Technology, Kalyan VeeramachaneniMassachusetts Institute of Technology, Xipeng ShenNorth Carolina State University, Una-May O’ReillyMassachusetts Institute of Technology, Saman AmarasingheMIT
Link to publication Media Attached
pldi2015-papers10:05 - 10:30
Talk
Charith MendisMIT CSAIL, Jeffrey BosboomMIT CSAIL, Kevin WuMIT CSAIL, Shoaib KamilMIT CSAIL, USA, Jonathan Ragan-KelleyStanford, Sylvain ParisAdobe, Qin ZhaoGoogle, Saman AmarasingheMIT
Media Attached
pldi2015-papers10:30 - 10:55
Talk
William J. BowmanNortheastern University, Swaha MillerCisco Systems, Inc, Vincent St-AmourNortheastern University, R. Kent DybvigCisco Systems, Inc
Link to publication Media Attached