Schedule :
9:00 - 9:15am ET Opening remarks Organizers
9:15 - 9:45am ET Failure as a learning opportunity for growth Gilles Pokam
9:45 - 10:15am ET Can Chips Prove Their Own Correctness? Siddharth Garg
New York University
10:15am - 10:30am ET Break
10:30am - 10:50am ET CRAP: Collecting Resources Across different Processing levels
Samuel Thomas
Brown University

Near-Memory Processing (NMP) is an emerging technology that can help accelerate pointer-chasing applications. However, it is necessary to invoke further evaluation of NMP on workloads that are more complex than data structures. We identify garbage collection as a more complex application for NMP. In this paper, we demonstrate that we can get 2x performance improvement in short-lived processes and a 2.3x reduction in L2 traffic by integrating NMP into the built-in Java garbage collector. However, we will discuss architectural reasons why these results do not extend to long-lived processes. We will discuss why these results should still be encouraging motivation for NMP-awareness in the JDK. View Paper

10:50am - 11:10am ET Too Noisy To Extract : Pitfalls of Model Extraction Attacks
Mujahid Al Rafi
UC Merced

Deep learning solutions become one of the most important intellectual properties of the solution providers. A few studies raised the alarm about the leakage of important model parameters through model extraction attacks. This paper discusses the practicality of such attacks by exploring the baseline assumptions of the existing attack scenarios. View Paper

11:10am - 11:30am ET Homomorphically Encrypted Computation using Stochastic Encodings
Julie Hsiao
Facebook Reality Labs - Research

Homomorphic encryption (HE) is a privacy-preserving technique that enables computation directly over ciphertext. Unfortunately, a key challenge for HE is that implementations can be impractically slow and have limits on computation that can be efficiently implemented. For instance, in Boolean constructions of HE like TFHE, arithmetic operations need to be decomposed into constituent elementary logic gates to implement so performance depends on logical circuit depth. For even heavily quantized fixed-point arithmetic operations, these HE circuit implementations can be slow. This paper explores the merit of using stochastic computing (SC) encodings to reduce the logical depth required for HE computation to enable more efficient implementations. Contrary to computation in the plaintext space where many efficient hardware implementations are available, HE provides support for only a limited number of primitive operators and their performance may not directly correlate to their plaintext performance. Our results show that by layering SC encodings on top of TFHE, we observe similar challenges and limitations that SC faces in the plaintext space. Additional breakthroughs would require more support from the HE libraries to make SC with HE a viable solution. View Paper

11:30am - Noon ET Industry and its Academic Research -- How does it work? Mondira Pant
Noon ET The End. Discussion, Feedback.

Bringing historical perspectives to NOPE

At MICRO 2019, Lynn Conway gave a keynote describing her personal story and the "techno-social" factors which led to her contributions being undervalued and unseen. Inspired by her perspective and call to action, we aim to rebrand the aims and goals NOPE to be more inclusive of historical perspectives and descriptions of how technical concepts came to be commonplace.

NOPE will remain a place for open, honest port-mortems of research projects which ran into unexpected limitations and resulted in lessons learned. In addition, it will offer a venue to discuss contributions that have been underappreciated and misconstrued over time. In this way, the goals of NOPE are to reflect on negative outcomes, shed light on the origin of ideas, and offer a venue to revise our understanding and uncover opportunities to move forward by reflecting on mistakes that can be made throughout the research process.

Why do we need to talk about negative results?

Not all research projects end up with positive results. Sometimes ideas that sound enticing at first run into unexpected complexity, high overheads, or turn out simply infeasible. Such projects often end up in a proverbial researcher's drawer, and the community as a whole is not aware of dead-end or hard-to-advance research directions. NOPE is a venue that encourages publishing such results in all their "badness".

What is a "good failure"?

The best negative results help us learn from our mistakes. They can illuminate hidden obstacles or demonstrate why we need a change of course. An ideal submission to NOPE has a novel idea which sounds plausible from first principles or design intuition, but yields little to no improvement (in performance, power, area, …) in practice. The paper drills down into the reasons for the lack of improvement and proposes a plausible explanation – different technology trends, unexpected implementation complexity.

Prior NOPE Workshops

NOPE 2021 Virtal Event
NOPE 2020 Lausanne, Switzerland (postponed)
NOPE 2019 Providence, RI
NOPE 2017 Cambridge, MA
NOPE 2016 Taipei, Taiwan
NOPE 2015 Waikiki, HI
(with MICRO 2015-2017)

Call for Papers

Our goal is to find papers which the community can learn from and might otherwise have trouble finding a suitable venue, so we take a broad view of what constitutes a "negative" result.

We invite submissions from all sub-areas of systems and computer architecture. Submissions should focus on discussing historical perspectives, uncovering a misunderstood or misappropriated technical concept, analyzing the reasons for failure, especially in light of underlying assumptions. Submissions based on opinion, speculation, and non-fundamental circumstances ("there was a bug in the simulator") are not encouraged, as they do not provide concrete evidence as to whether an idea is bad. Topics of interest include:

Important dates

Paper submission: February 14, 2022
Author notification: February 16, 2022
Camera-ready version: February 23, 2022

Submission Guidelines

We believe in substance over style, and we encourage authors to prioritize delivering their message over conforming to a particular template. That being said, we anticipate papers will be 2 pages, and we encourage authors to use a two-column format. Papers need not be anonymized.

Additionally, we ask that you also include a short, 1-paragraph abstract in your submission email. This should be suitable for inclusion on the NOPE website and program handouts.

Accepted submissions are expected to prepare a poster or short presentation to foster discussion.


Please submit your papers via email to: by 5:00pm ET on the deadline.


Lillian Pentecost, Harvard
Udit Gupta, Harvard
Thierry Tambe, Harvard
Jeff (Jun) Zhang, Harvard
David Brooks, Harvard
Brandon Reagen, NYU / Facebook


Questions? Send us an email.