On the Effective Parallel Programming of Multi-core Processors PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus prof. ir. K.C.A.M. Luyben, voorzitter van het College voor Promoties, in het openbaar te verdedigen op dinsdag 7 december 2010 om 10.00 uur door Ana Lucia VARBˆ ANESCUˇ Master of Science in Architecturi Avansate de Calcul, Universitatea POLITEHNICA Bucure¸sti, Romˆania geboren te Boekarest, Roemeni¨e. Dit proefschrift is goedgekeurd door de promotor: Prof. dr. ir. H.J. Sips Samenstelling promotiecommissie: Rector Magnificus voorzitter Prof.dr.ir. H.J. Sips Technische Universiteit Delft, promotor Prof.dr.ir. A.J.C. van Gemund Technische Universiteit Delft Prof.dr.ir. H.E. Bal Vrije Universiteit Amsterdam, The Netherlands Prof.dr.ir. P.H.J. Kelly Imperial College of London, United Kingdom Prof.dr.ing. N. T¸˜apu¸s Universitatea Politehnic˜aBucure¸sti, Romania Dr. R.M. Badia Barcelona Supercomputing Center, Spain Dr. M. Perrone IBM TJ Watson Research Center, USA Prof.dr. K.G. Langendoen Technische Universiteit Delft, reservelid This work was carried out in the ASCI graduate school. Advanced School for Computing and Imaging ASCI dissertation series number 223. The work in this dissertation was performed in the context of the Scalp project, funded by STW-PROGRESS. Parts of this work have been done in collaboration and with the material support of the IBM T.J. Watson Research Center, USA. Part of this work has been done in collaboration with the Barcelona Supercomputing Center, and supported by a HPC Europa mobility grant. Copyright c 2010 by Ana Lucia Varbanescu. All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without the prior permission from the author. The author can be contacted at [email protected]. ISBN/EAN: 978-90-8570-708-0 Printed in the Netherlands by W¨ohrmann Print Service (www.wps.nl). Acknowledgments There have been many moments in which my PhD felt a lonely fight against the world. But now, when writing the very last pages of my thesis - the acknowledgements - I realize I’ve been lucky to have a lot of people by my side, all the way. I try to thank all of them here - in a vague chronological order. As the list can only be limited and therefore prone to omissions - I will probably fail. For those of you that I might have omitted: please accept my apologies, my thanks, and a glass of wine from me, to wash away the sorrow. I want to thank Prof. Nicolae Tapus, for his guidance during my academic years in Romania, and for accepting to be part of my committee. I am grateful to late Prof. Irina Athanasiu, for her continuous encouragement, and for her role in my first collaboration with TUDelft. And I want to thank Prof. Sorin Cotofana, for making my first encounters with TUDelft, The Netherlands, and the Dutch interesting and comfortable. Special thanks go to Prof. Henk Sips, my supervisor, for his help and support, for putting up with all my last minute ideas and panic moments (starting from that CPC’06 paper). I owe him thanks for his patience in waiting for my thesis, who was “almost ready” for many months, but also for our enlighting discussions about non-scientific topics such as sailing, traveling, wine, or earrings. I’d like to thank Prof. Arjan van Gemund for his help on PAM-SoC and the SCALP project, and for the valuable insight in performance analysis, modeling, and prediction. Furhter thanks go to the other SCALP members: Dr. Maik Nijhuis, Dr. Herbert Bos, and Prof. Henri Bal (from Vrije Universiteit Amsterdam) - for our collaboration in building SP@CE. One extra “thank you” to Prof. Henri Bal for his useful comments on the draft of my thesis. Thanks to Paul Stravers and Jos van Eindhoven (currently at VectorFabrics) for their help with the SpaceCAKE architecture itself, and for the valuable insights in the pragmatic thinking of “the industry”. I would like to thank Dr. Michael Perrone, my two-time manager at IBM TJ Watson Research Center - his enthusiasm for the Cell/B.E., and his ability to quickly detect good solutions from bad ones and extract the essence from any (vague) idea played an important role in my work so far. Thank you, Michael, for your help and support, for the subtle ways you found to motivate me, and for the continuous interest you showed in my career. Last, but not least, thank you for the suggestions made for improving this thesis. Additional thanks go to the other members of the Cell Solutions team with whom I worked at TJ Watson - Gordon Braudaway, Daniele Scarpazza, Fabrizio Petrini, and Virat Agarwal - for sharing with me some of the secrets of Cell/B.E. programming. I owe thanks to Rosa Badia and Xavier Martorell, with whom I worked for six weeks at the Barcelona Supercomputing Center (and continued to collaborate afterwards). Our work on classifying, i ii comparing, and evaluating a large variety of programming models, has helped me understand more of the subtle effects that programmability and productivity have on platform adoption and performance. Thanks to Ian Buck and Stephen Jones for my nice summer internship in the CUDA team from NVIDIA, where I had to opportunity to see how difficult it is to build the right software tools and models in a hardware-dominated environment. I’d like to thank Prof. Paul Kelly for accepting to be part of my committee, for his comments on the draft of my thesis, as well as for our occassional, yet very interesting discussions on parallelism and performance. And thank you, Prof. Joerg Keller, for our fruitful collaboration, which I hope to maintain and improve. I would like to end my “professional” acknowledgements by thanking two of my most stable scientific partners, and friends: Dr. Rob van Nieuwpoort and Alexander van Amesfoort. Thanks, guys, for the smooth collaboration in our various projects together, and for our entertaining discussions. I surely hope we will keep working together for a while longer. I am grateful for all the help and support I got from my friends and my family. Thanks, Monel and Mihaitza for always finding the energy to spend some time with me. Thanks, Robert, for keeping me up to date with the pubs in Bucharest. Thanks Nicoleta, Ervin and Anca Vitos, and Michou for your good thoughts from far away. Thank you, Ana Maria O. and Corina for the fun in Amsterdam, and for geek girls nights out. Thank you, Karan, for being so close to me from the other side of the world. Thank you, Ivo, for the wine and cheese evenings, and for being such a great officemate - no wonder I never wanted to work from home! Thanks, Otto, for your help with the Dutch in all its/their forms, and for your visits on the dark side of the corridor. Thanks, Pawel and Alex F., for making weekends at the TUDelft bearable. These years, basketball has been an important part of my life. I am grateful to my teammates, trainers, and coaches from Punch, for the many fun memories on and off court. Special thanks to Tessa, Marije, Marta, Charlotte, Siri, Bridgit, and Jill for their kind friendship outside the club. Thanks to “my” Heren3 team, for accepting such a shouting coach, and for teaching me the inner beauty of pink. Thank you, Remus, Coco, Patricia, and Rita for the many crazy tournaments we have played together - I enjoyed them a lot. And thank you very much, Maider, for extending our friendship so far beyond basketball. I would not remember my time in the US with that much pleasure if it wouldn’t have been for the friends I made there. Thank you, Janet, for your kindness and your care during the months I spent in your house. Thank you, Nicolas, for the biking trips and for your restless efforts to make me understand the beauty of american football (sorry, I still don’t get it). Thank you, Marcio, for the afternoon coffees. Thank you, Virat and Leo, for the tennis matches and the movie evenings in the conference rooms. Thank you, Mesut, for the wine and cheese parties at Janet’s. Thank you, Vlad, for showing me some of the beautiful places of California. Finally, there are four more special people in my life, to whom I am most grateful - without them, all these years would have been a lot tougher. Thank you, Ancutza, for being my best friend all these years, for being there in the cloudiest of days (and those are plenty in The Netherlands!), for listening and for talking, for always being honest, direct, and fair. Thank you, Alexandru, for your love, for putting up with my mood swings and pre-deadline panic, for standing by my side when I needed it, for believing in me and for encouraging me; thank you for your patience and your calm support. And thank you, Mom and Dad, for teaching me to work hard and to never give up, and for inspiring me to be the best in what I do. Thank you for being so proud of me. Thank you, Mom, for teaching me the magic powers of good food. Thank you, Dad, for these last 25 years of basketball and computing machineries. Thank you for everything. I love you very very much.