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FYI, The LLVM Performance Workshop will be held at CGO 2017. The workshop is co-located with CC, HPCA, and PPoPP. If you are interested in attending the workshop, please register at the CGO website: http://cgo.org/cgo2017/workshops.html When: Saturday February 4th, 2017 Where: Austin, Texas, USA ---- Hi, CGO workshop and tutorial organizers, This is a friendly reminder that early registration rates for CGO (and its workshops/tutorials) ends on January 6: http://cgo.org/cgo2017/registration.html And the early ho...

An LLVM Performance Workshop will be held at CGO 2017. The workshop is co-located with CC, HPCA, and PPoPP. If you are interested in attending the workshop, please register at the CGO website: http://cgo.org/cgo2017/workshops.html Call for Speakers We invite speakers from academia and industry to present their work on the following list of topics (including and not limited to:) - improving performance and size of code generated by LLVM, - improving performance of LLVM's runtime libraries, - tools deve...

Michael Spencer via llvm-dev <llvm-dev at lists.llvm.org> writes: > I've recently implemented profile guided section layout in llvm + lld using > the Call-Chain Clustering (C³) heuristic from > https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf > . In the programs I've tested it on I've gotten from 0% to 5% performance > improvement over standard PGO with zero cases of slowdowns and up to 15% > reduction in ITLB misses. > > > There are three parts to this implementation. > > The first is a...

I've recently implemented profile guided section layout in llvm + lld using the Call-Chain Clustering (C³) heuristic from https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf . In the programs I've tested it on I've gotten from 0% to 5% performance improvement over standard PGO with zero cases of slowdowns and up to 15% reduction in ITLB misses. There are three parts to this implementation. The first is a new llvm pass which uses branch freq...

Hi, I would like to learn the details regarding what exactly PGO does for basic block layout/code placement optimizations in llvm. Could you please point me to some descriptions? Is it close to this paper (Karl Pettis and Robert C. Hansen. 1990. Profile guided code positioning. PLDI'90) http://perso.ensta-paristech.fr/~bmonsuez/Cours/B6-4/Articles/papers15.pdf? Whether it is purely

Hi Rafael, On 07/31/2017 04:20 PM, Rafael Avila de Espindola via llvm-dev wrote: > However, do we need to start with instrumentation? The original paper > uses sampling with good results and current intel cpus can record every > branch in a program. > > I would propose starting with just an lld patch that reads the call > graph from a file. The format would be very similar to

...okup(S); }); } +// Sort sections by the profile data provided in the .note.llvm.callgraph +// sections. +// +// This algorithm is based on Call-Chain Clustering from: +// Optimizing Function Placement for Large-Scale Data-Center Applications +// https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf +// +// This first builds a call graph based on the profile data then iteratively +// merges the hottest call edges as long as it would not create a cluster larger +// than the page size. All clusters are then sorted by a density metric to +// further improve locality. +template &...

...okup(S); }); } +// Sort sections by the profile data provided in the .note.llvm.callgraph +// sections. +// +// This algorithm is based on Call-Chain Clustering from: +// Optimizing Function Placement for Large-Scale Data-Center Applications +// https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf +// +// This first builds a call graph based on the profile data then iteratively +// merges the hottest call edges as long as it would not create a cluster larger +// than the page size. All clusters are then sorted by a density metric to +// further improve locality. +template &...