Professor Josep Torrellas
Saburo Muroga Professor of Computer Science
University of Illinois at Urbana-Champaign
(torrella@illinois.edu)
Google Scholar,
CV August 2022


Looking for Graduate Students:
The SRC/DARPA JUMP 2.0 ACE Center for Evolvable Computing is starting in January 2023. This 5-year 21-Principal Investigator project is focused on transforming distributed computing, substantially improving its energy efficiency and performance. See the Official Announcement, as well as the SRC announcements (here and here) and the
DARPA announcement. I am looking for graduate students who want to get involved in the Center. It is a great opportunity for individuals who are looking to learn and perform research on cross-disciplinary issues in computing systems, interact with students and senior researchers across the community, and have a close collaboration with computer industry leaders.
If interested, please send an email with your CV to torrella@illinois.edu.
JOSEP TORRELLAS BIO:
Josep Torrellas is the Saburo Muroga Professor of Computer Science at the University of Illinois at Urbana-Champaign (UIUC). He is the
Director of the SRC/DARPA JUMP 2.0 ACE Center for Evolvable Computing, past Co-Leader of an Intel Strategic Research Alliance (ISRA) on Computer Security, and past Director of the
Illinois-Intel Parallelism Center (I2PC).
JOSEP TORRELLAS BIO:
Josep Torrellas is the Saburo Muroga Professor of Computer Science at the University of Illinois at Urbana-Champaign (UIUC). He is the
Director of the SRC/DARPA JUMP 2.0 ACE Center for Evolvable Computing, past Co-Leader of an Intel Strategic Research Alliance (ISRA) on Computer Security, and past Director of the
Illinois-Intel Parallelism Center (I2PC).
Torrellas has made contributions to shared-memory multiprocessor architectures and thread-level speculation (TLS) over more than thirty years. He was the first to apply TLS ideas to parallel architectures and programs: He used speculative multithreading to eliminate stalling due to synchronization (Speculative Synchronization), identify and debug data races (ReEnact), monitor memory accesses (I-Watcher), provide fault tolerance (ReVive), and inexpensively enforce sequential consistency (BulkSC). Some of these ideas impacted IBM's Blue Gene and other commercial machines. Torrellas was part of the design team of IBM’s PERCS Multiprocessor, an architecture for productivity. The team considered some of his TLS mechanisms, as well as processing-in-memory features inspired by his FlexRAM Intelligent Memory project.
Using mechanisms inspired by TLS, Torrellas developed the Bulk Architecture, an out-of-the-box scalable shared-memory multiprocessor for programmability that was influential within Intel as part of the Illinois-Intel Parallelism Center. Torrellas also applied TLS ideas to develop Record and deterministic Replay (RnR) architectures and, together with Intel, he built QuickRec, the first RnR hardware prototype, which used FPGAs to extend Intel’s cores and caches for RnR.
Torrellas has made contributions to multiprocessor architectures, NUMA organizations, cache coherence protocols, hardware synchronization, and prefetching schemes. In recognition, the government made his I-ACOMA multiprocessor one of the Ten Design-Point Studies funded nationwide to attain Petaflop machines. He was involved in the Stanford DASH and Illinois Cedar experimental multiprocessors. His early work on false sharing and cache behavior of OS and commercial workloads influenced compiler writers and architects of early parallel machines, such as the Silicon Graphics Origin2000. Torrellas was also co-leader of the Intel Runnemede Extreme-Scale multiprocessor, a machine designed for energy efficiency that impacted Intel’s high-end architectures.
Torrellas received the 2021 IEEE Computer Society Harry H. Goode Memorial Award ”for contributions to energy efficient and programmable shared-memory multiprocessor architectures”, the 2017 UIUC Campus Award for Excellence in Graduate Student Mentoring, and the 2015 IEEE Computer Society Technical Achievement Award ”for pioneering contributions to shared-memory multiprocessor architectures and thread-level speculation”. He has received a Google Faculty Research Award, IBM Partnership Awards, Intel Research Council Awards, and an NSF Young Investigator Award. He was a Willett Faculty Scholar at Illinois (2002-9). He is a Fellow of IEEE, ACM, and AAAS. He has received many Best Paper Awards and a High-Impact Paper Award.
Torrellas has mentored generations of computer architects. Of his 48 Ph.D. graduates, over a dozen are faculty at top US academic institutions, including Martínez (Cornell), Solihin (UCF), Huang (Rochester), Prvulovic (Gatech), Renau (UCSC), Tuck (NCSU), Ceze (Washington), Teodorescu (OSU), Ahn (Pittsburgh), Muzahid (Texas A&M), Karpuzcu (Minnesota), Qian (Purdue), Honarmand (Stony Brook), Yan (MIT), and Skarlatos (CMU).
Torrellas has served as the Chair of the IEEE CS Technical Committee on Computer Architecture (TCCA) (2018-22). He has also served in the Board of Directors of the Computing Research Association (CRA) (2016-19), has been a Council Member of CRA’s Computing Community Consortium (CCC) (2011-14), and has served as a Member of the U.S. National Academies Board on Army Research and Development (2018-23). He currently serves in the International Roadmap for Devices and Systems (IRDS). He has co-organized many funding and visioning workshops. His workshops on Advancing Computer Architecture Research helped usher NSF’s XPS Program.
Prior to being at UIUC, Torrellas received a Ph.D. from Stanford University.
- « Publications »
- « Curr. Vitae »
- « Students Graduated»
Torrellas leads
The i-acoma Architecture Group, which focuses on new processor,
memory, and system technologies and organizations to build novel multiprocessor
computer architectures. Two examples of projects we have done in the past:
- A novel multicore architecture for programmability:
The Bulk Multicore Architecture (Communications of the ACM, December 2009). [Presentation slides].
EE Times article that discusses the Bulk Multicore.
Dr. Dobb's Journal discussion of the Bulk Multicore.
Making Parallel Programming Easy: Research Contributions from Illinois, a book summarizing the accomplishments of the Illinois-Intel Parallelism Center (I2PC).
This project is funded under the Illinois Intel Parallelism Center (I2PC). - An extreme-scale multiprocessor architecture designed from the
ground up for energy and power efficiency:
Thrifty: An Extreme-Scale Multiprocessor Architecture (IEEE Computer, November 2009). [Presentation slides].
Extreme-Scale Computer Architecture: Energy Efficiency from the Ground Up (DATE, March 2014).
This work is part of an Intel-lead DARPA project that aims to design an Extreme-Scale computer.
Intel blog on the DARPA project.
This project is funded by DARPA under UHPC and DOE.
Examples of Architectures We Designed in the Past:
-
"QuickRec: A Hardware Prototype for Recording and Deterministically Replaying
Multithreaded Programs in the Intel Architecture".
This prototype has been developed in collaboration with Intel,
and is described in the QuickRec ISCA-2013 paper.
-
"Runnemede: An Chip Multiprocessor for Extreme-Scale Computing".
This manycore chip has been designed in collaboration with Intel, and is
described in the Runnemede HPCA-2013 paper.
Recent News (whole list at the News Tab):
- March 2023: Three papers are accepted in ISCA 2023.
- January 2023: One paper is accepted in ASPLOS 2023.
- January 2023: Josep Torrellas is the Director of the SRC/DARPA JUMP 2.0 ACE Center for Evolvable Computing. See the
Center Announcement, as well as the SRC announcements (here and here) and the
DARPA announcement.
- November 2022: One paper is accepted in PPoPP 2023.
- October 2023: Two papers are accepted in HPCA 2023.
- March 2022: One paper is accepted in ISCA 2022.
- January 2022: Two papers are accepted in IEEE Top Picks in Computer Architecture 2022:
Distributed Data Persistency (MICRO 21) and
Maya: Using Formal Control to Obfuscate Power Side Channels (ISCA 21) .
- November 2021: Two papers are accepted in ASPLOS 2022.
- September 2021: One paper is accepted in MICRO 2021.
- May 2021: The SDO paper receives the
First Place in the Inaugural Intel Hardware Security Academic Award.
- May 2021: CSL article on the Draco System Call Security Software upstreaming to Linux v5.11.
- April 2021: IBM-Illinois C3SR center article on
our upstreaming of
the Draco System Call Security Software to Linux v5.11.
- March 2021: Two papers are accepted in ISCA 2021.
- February 2021: Torrellas received the
IEEE Computer Society
2021 Harry H. Goode Memorial Award, "For contributions to energy efficient and programmable
shared-memory multiprocessor architectures.". Also see article from the Computer Science Department.
- January 2021: One Paper (BabbleFish) in the 12-paper IEEE Micro 2021
Top Picks from Computer Architecture Conferences, plus one
Honorable Mention (Elastic Cuckoo Page Tables).
- December 2020: The upstreamed Draco is featured in
Linux Security at Phoronix.
- December 2020: Draco has been upstreamed in the Linux Kernel.
- December 2020: One paper is accepted in HPCA 2021 and two papers in ASPLOS 2021.
- August 2020:
Raghavendra Pothukuchi graduated and will start as a Postdoctoral Researcher at Yale University
with Prof. Abhishek Bhattacharjee.
- August 2020:
Dimitrios Skarlatos graduated and will start as an Assistant Professor in the CS Department at Carnegie Mellon University.
- July 2020: Four papers are accepted in MICRO 2020.
- July 2020: STT paper selected for Research Highlight, Communications of the ACM (CACM).
- March 2020: Two papers are accepted in ISCA 2020.
- March 2020:
The University of Illinois Shines at ISCA 2019.
- March 2020: Best Paper Award at ASPLOS 2020. Also see article from the Computer Science Department.
Video
of the talk "Elastic Cuckoo Page Tables: Rethinking Virtual Memory Translation for Parallelism".
- February 2020: Torrellas gives the HPCA/PPoPP/CGO 2020 Keynote.
Video
of the HPCA/PPoPP/CGO 2020 Keynote
by Josep Torrellas on "Interdisciplinary Research at a Time of Pervasive Changes".
- January 2020: Two Papers (MicroScope and STT) in the 12-paper IEEE Micro 2020
Top Picks from Computer Architecture Conferences, plus one Honorable Mention (Vertical Processors).
- March 2023: Three papers are accepted in ISCA 2023.
- January 2023: One paper is accepted in ASPLOS 2023.
- January 2023: Josep Torrellas is the Director of the SRC/DARPA JUMP 2.0 ACE Center for Evolvable Computing. See the Center Announcement, as well as the SRC announcements (here and here) and the DARPA announcement.
- November 2022: One paper is accepted in PPoPP 2023.
- October 2023: Two papers are accepted in HPCA 2023.
- March 2022: One paper is accepted in ISCA 2022.
- January 2022: Two papers are accepted in IEEE Top Picks in Computer Architecture 2022: Distributed Data Persistency (MICRO 21) and Maya: Using Formal Control to Obfuscate Power Side Channels (ISCA 21) .
- November 2021: Two papers are accepted in ASPLOS 2022.
- September 2021: One paper is accepted in MICRO 2021.
- May 2021: The SDO paper receives the First Place in the Inaugural Intel Hardware Security Academic Award.
- May 2021: CSL article on the Draco System Call Security Software upstreaming to Linux v5.11.
- April 2021: IBM-Illinois C3SR center article on our upstreaming of the Draco System Call Security Software to Linux v5.11.
- March 2021: Two papers are accepted in ISCA 2021.
- February 2021: Torrellas received the IEEE Computer Society 2021 Harry H. Goode Memorial Award, "For contributions to energy efficient and programmable shared-memory multiprocessor architectures.". Also see article from the Computer Science Department.
- January 2021: One Paper (BabbleFish) in the 12-paper IEEE Micro 2021 Top Picks from Computer Architecture Conferences, plus one Honorable Mention (Elastic Cuckoo Page Tables).
- December 2020: The upstreamed Draco is featured in Linux Security at Phoronix.
- December 2020: Draco has been upstreamed in the Linux Kernel.
- December 2020: One paper is accepted in HPCA 2021 and two papers in ASPLOS 2021.
- August 2020: Raghavendra Pothukuchi graduated and will start as a Postdoctoral Researcher at Yale University with Prof. Abhishek Bhattacharjee.
- August 2020: Dimitrios Skarlatos graduated and will start as an Assistant Professor in the CS Department at Carnegie Mellon University.
- July 2020: Four papers are accepted in MICRO 2020.
- July 2020: STT paper selected for Research Highlight, Communications of the ACM (CACM).
- March 2020: Two papers are accepted in ISCA 2020.
- March 2020: The University of Illinois Shines at ISCA 2019.
- March 2020: Best Paper Award at ASPLOS 2020. Also see article from the Computer Science Department. Video of the talk "Elastic Cuckoo Page Tables: Rethinking Virtual Memory Translation for Parallelism".
- February 2020: Torrellas gives the HPCA/PPoPP/CGO 2020 Keynote. Video of the HPCA/PPoPP/CGO 2020 Keynote by Josep Torrellas on "Interdisciplinary Research at a Time of Pervasive Changes".
- January 2020: Two Papers (MicroScope and STT) in the 12-paper IEEE Micro 2020 Top Picks from Computer Architecture Conferences, plus one Honorable Mention (Vertical Processors).
Some Recent Publications:
- Graphite: Optimizing Graph Neural Networks on CPUs Through Cooperative Software-Hardware Techniques, ISCA 2022.
[Presentation slides].
- Parallel Virtualized Memory Translation with Nested Elastic Cuckoo Page Tables, ASPLOS 2022.
[Presentation slides].
- Pinned Loads: Taming Speculative Loads in Secure Processors, ASPLOS 2022.
[Presentation slides].
- Distributed Data Persistency, MICRO 2021.
[Presentation slides].
- Maya: Using Formal Control to Obfuscate Power Side Channels,
ISCA 2021.
[Presentation slides].
- Execution Dependence Extension (EDE): ISA Support for Eliminating Fences,
ISCA 2021.
[Presentation slides].
- Jamais Vu: Thwarting Microarchitectural Replay Attacks,
ASPLOS 2021.
[Presentation slides].
- Speculative Interference Attacks: Breaking Invisible Speculation Schemes,
ASPLOS 2021.
[Presentation slides].
- WiDir: A Wireless-Enabled Directory Cache Coherence Protocol,
HPCA 2021.
[Presentation slides].
Software Released:
- VARIUS and VARIUS-NTV: A model of within-die process variation and resulting timing errors in manycores for microarchitects.
- SESC: A cycle accurate architectural simulator that models a very wide set of architectures: superscalars, multiprocessors, processors in memory, and thread-level speculation.
Emphasis Research Areas:
The main emphasis research areas in the group are:
- Multiprocessor organization and system design
- Speculative multithreading
- Hardware reliability and variability
- Support for software reliability
- Low-power design
- Old Projects
Currently Teaching:
CS533: Parallel Computer Architectures.
Contact Information
Josep Torrellas
4231 Thomas M. Siebel Center for Computer Science.
University of Illinois.
201 N. Goodwin Ave.
Urbana, IL. 61801.
Phone (217) 244-4148, fax 217-265-6582.
E-mail: torrella@illinois.edu
Administrative Assistant
Madeleine Garvey,
Thomas M. Siebel Center for Computer Science.
University of Illinois.
201 N. Goodwin Ave.
Urbana, IL. 61801.
Phone (217) 300-6342.
E-mail: mgarvey@illinois.edu
4231 Thomas M. Siebel Center for Computer Science.
University of Illinois.
201 N. Goodwin Ave.
Urbana, IL. 61801.
Phone (217) 244-4148, fax 217-265-6582.
E-mail: torrella@illinois.edu
Administrative Assistant
Madeleine Garvey,
Thomas M. Siebel Center for Computer Science.
University of Illinois.
201 N. Goodwin Ave.
Urbana, IL. 61801.
Phone (217) 300-6342.
E-mail: mgarvey@illinois.edu


