SIMDRAM: A Framework for Bit-Serial SIMD Processing using DRAM

Watch our recent talks at ASPLOS 2021!

Nastaran Hajinazar, Geraldo F. Oliveira, Sven Gregorio, Joao Dinis Ferreira, Nika Mansouri Ghiasi, Minesh Patel, Mohammed Alser, Saugata Ghose, Juan Gomez-Luna, and Onur Mutlu,
SIMDRAM: A Framework for Bit-Serial SIMD Processing using DRAM”
Proceedings of the 26th International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS), Virtual, March-April 2021.
[2-page Extended Abstract]
[Short Talk Slides (pptx) (pdf)]
[Talk Slides (pptx) (pdf)]
[Short Talk Video (5 mins)]
[Full Talk Video (27 mins)]


Interview with Mohammed Alser: on his recent papers and his future work

Mohammed Alser
 is a Senior Researcher and Lecturer with SAFARI. 
He was previously a PhD student in SAFARI, co-advised with Can Alkan. Mohammed co-teaches two Projects and Seminars courses on Genome Sequencing Analysis and Mobile Genomics along with the Seminar on Computer Architecture.  We recently interviewed Mohammed for the January 2021 issue of the SAFARI Newsletter.  

You have been busy this past year, and have published quite a few papers. Your recent work, SneakySnake, was recently published in Bioinformatics. This is an important work in improving computations for genome analysis. Can you tell us more about the significance of this work, and what broader impacts you hope for it?

SneakySnake is one of the projects that I enjoyed the most working on. We try in this work to significantly reduce the time spent on finding the similarities and differences between two genomic sequences without sacrificing solution optimality. Finding the similarities and differences between two sequences is a well-known computer science problem, called approximate string matching (ASM), which is solved using computationally expensive algorithms.

SneakySnake quickly finds the sequence pairs that have a large (greater than a user-defined threshold) number of differences and prevents applying computationally expensive algorithms for these sequence pairs, as such sequence pairs are usually not useful for genomic studies. SneakySnake is inspired by the single net routing (SNR) problem in VLSI design that was introduced in 1976. SneakySnake is the first work that proposes to convert the ASM problem into an instance of the SNR problem, which provides several key benefits as we discussed in the paper, and proposes a new efficient algorithm for comparing genomic sequences at scale.

SneakySnake is very beneficial for analyzing both short (e.g., Illumina) and long (e.g., nanopore) sequences as it accelerates the analysis of genomic sequences by up to two orders of magnitude compared to the state-of-the-art algorithms. SneakySnake works efficiently and fast on modern CPU, FPGA, and GPU architectures, which can potentially enable new applications of genome sequencing such as rapid surveillance of disease outbreaks including Ebola and COVID-19, near-patient testing, and bringing precision medicine to remote locations, without the need for large infrastructure.

One of the Bioinformatics journal’s reviewers states that: “SneakySnake is a valuable contribution to bioinformatics and it was innovative to reduce the ASM problem to the SNR problem in VLSI CAD”.

You also recently published Accelerating Genome Analysis, which reviews the improvements made in hardware accelerators for genome analysis. What are your take away messages from this paper, and what do you see as future priorities in hardware improvements for genome analysis?

Most speedup comes from parallelism enabled by novel architectures and algorithms. We need to develop acceleration solutions that exploit new efficient hardware-aware algorithms, hardware/software co-design, and hardware accelerators to achieve a high degree of parallelism.

Accelerating the entire genome analysis pipeline is important. Accelerating only a single step of genome analysis is not an effective acceleration approach as it limits the overall achieved speedup according to Amdahl’s Law.

Genome analysis is currently heavily bottlenecked by data movement. We need to reduce the high amount of data movement that takes place during genome analysis. Moving data (1) between compute units and main memory, (2) between multiple hardware accelerators, and (3) between the sequencing machine and the computer performing the analysis incurs high costs in terms of execution time and energy. These costs are a significant barrier to enabling efficient analysis that can keep up with sequencing technologies.

The need for flexible hardware architectures. We need to develop flexible hardware architectures that do not conservatively limit the range of supported parameter values at design time. Rapid changes in sequencing technologies (e.g., those that result in high sequencing error rates and longer read lengths) can quickly make specialized hardware with restricted parameter values obsolete.

The need for new genomic data formats. We need to adapt existing genomic data formats for hardware accelerators or develop more efficient file formats to maximize the benefits of hardware accelerators and reduce resource utilization.

Looking into the future, building a genome sequencing machine that provides the entire genome as a single string, rather than its short subsequences, might be possible. However, we believe that the need for hardware acceleration of whole-genome analysis will continue to remain necessary. We also believe performing genome analysis inside the sequencing machine itself can significantly improve efficiency by eliminating sequencer-to-computer data movement.

Your work has many topical applications that are highly relevant to society, including COVID modeling. Can you talk a bit about this, and your future research directions?

As the entire world is largely negatively impacted by the recent COVID-19 outbreak, we believe that everyone can help to end this pandemic based on their skills, expertise, and available resources. At SAFARI research group, we are helping with two main directions.

We are working on developing an accurate and configurable prediction model that evaluates the existing mitigation measures that the government applies in a region and provides suggestions on what strength the future mitigation measures should be. We are quantifying the spread of COVID-​19 in Switzerland (as a use-case) by calculating the daily reproduction number of COVID-19, which quantifies how many people are infected on average by an infected person. The reproduction number is directly affected by the mitigation measures that the government applies to a region. We are also considering other important factors such as daylight temperature that significantly affect the spread of COVID-​19 as we observed during the year 2020.

We are also working on developing new algorithms and hardware accelerators that perform fast and accurate metagenomic profiling for assessing microbial diversity, identifying potential new species, and investigating microbiomes associated with COVID-19 and other diseases. Performing genomic tests at scale during a pandemic highlights the dire need for building efficient specialized hardware that is both scalable and portable to enable genome analysis anywhere and anytime. We hope that the progress we make in this direction will also enable new applications that benefit human life and society.

Mohammed Alser, Taha Shahroodi, Juan-Gomez Luna, Can Alkan, and Onur Mutlu, SneakySnake: A Fast and Accurate Universal Genome Pre-Alignment Filter for CPUs, GPUs, and FPGAsBioinformatics, December 2020.
Paper PDF | Paper link Bioinformatics | Source Code

Mohammed Alser, Zulal Bingol, Damla Senol Cali, Jeremie Kim, Saugata Ghose, Can Alkan, and Onur Mutlu, Accelerating Genome Analysis: A Primer on an Ongoing Journey, IEEE MICRO, September/October 2020.
Paper | Slides (pptx) (pdf)

Read the latest edition of our SAFARI Newsletter

Dear SAFARI friends,

Happy New Year!  We are excited to share our group highlights with you in this second edition of the SAFARI newsletter:

In this second edition of the SAFARI newsletter, we share our research, teaching and outreach highlights from 2020, and look ahead to a new and inspiring future in 2021.

We wish you a wonderful 2021, in all aspects of your lives!

Onur Mutlu

Award: Jisung Park was awarded a Postdoctoral Research Fellowship

Jisung Park was awarded a Postdoctoral Research Fellowship from the National Research Foundation of Korea for his project on “Storage System Design for Machine Learning Applications”.

Congratulations Jisung — We look forward to having you in the group for another year!

The NRF Postdoctoral Research Fellowship supports promising Korean postdoctoral researchers in all fields of science and engineering for one year.



Paper: Accelerating Genome Analysis: A Primer on an Ongoing Journey

In our new paper, we describe the ongoing journey in significantly improving the performance of read mapping: Accelerating Genome Analysis: A Primer on an Ongoing Journey

Mohammed AlserZülal BingölDamla Senol CaliJeremie KimSaugata GhoseCan AlkanOnur Mutlu

Paper, arXiv:
Paper, IEEE Micro:

Invited Talks

Mohammed Alser:
A Roadmap for Fast and Efficient Genome Analysis, Univ. of Tokyo, Shirokanedai:

Mohammed Alser:
Accelerating Genome Analysis Using New Algorithms and Hardware Designs, Univ. of Tokyo:…

Onur Mutlu:
AACBB 2019 Keynote Talk:

Award: TRRespass wins the Best Paper Award at IEEE S&P!

Our recent paper “TRRespass: Exploiting the Many Sides of Target Row Refresh”, in collaboration with the Systems and Network Security Group at VU Amsterdam has been awarded the Best Paper Award at the 41st IEEE Symposium on Security and Privacy!

Congratulations to the authors: Pietro Frigo, Emanuele Vannacci, Hasan Hassan, Victor van der Veen, Onur Mutlu, Cristiano Giuffrida, Herbert Bos, and Kaveh Razavi

Rowhammer, the DRAM vulnerability that was supposedly fixed in DDR4 is not fixed in DDR4. The TRRespass attack shows that DIMMs from all 3 major vendors (good for 95% of the market) are still vulnerable.

Read the news story: NakedSecurity
Paper: “TRRespass: Exploiting the Many Sides of Target Row Refresh”
Talk Video
Source Code
Project Overview