Education
- University of Maryland, College Park (Sep 2010 - May 2014)
Ph.D. in Electrical and Computer Engineering
GPA: 4.0/4.0
- Indian Institute Of Technology (IIT), Guwahati,India (June 2001 - May 2005)
B.Tech. in Electronics and Communication Engineering
Research
- Optimizing Emerging AI/ML Applications
- Scalable Vector Search: optimizing approximate nearest neigbor (ANN) search on Intel hardware. Our work published in VLDB'23 and TMLR'24.
Here is the link to our scalable vector search library
- Designing efficient compute and memory architecture for emerging applications like Deep Learning
- Micro-architecture Research
- NVM based LLC: Proposed novel techniques to mitigate long NVM write latency (featured in ISCA-2018)
- Memory aware reordered source (MARS): to reshape the memory traffic for efficient memory bandwidth (US patent granted)
- Adaptive Width Aware Core (AWAC): we used simple heuristics to intelligently provision resources in the core dynamically (part of work featured in IEDM'2017)
- Scalable DRAM Refresh
- Comprehensive evaluation and survey of DRAM refresh mechanisms, trade-offs and penalties. We clarify prevalent confusions with refresh options and timings available in JEDEC specified DDR devices (featured in Transaction on Computers, 2015)
- Proposed simple modification in DRAM device to enable refreshes reduction with optimized auto-refresh commands rather than in-efficient row-level refresh commands. (featured in ISCA-2014)
- Energy Efficient Memory Systems
- Proposed novel techniques to simultaneously minimize two important types of DRAM energy components: background and refresh
- Our novel schemes called "Coordinated Refresh" schedule refresh operations and power down modes in an energy efficient fashion (featured in ISLPED-2013)
- High Capacity Non-Volatile Memory (NVM)
- Contributed in the design of parametrized simulation infrastructure to study NVMs, with a focus on utilizing commodity NAND Flash as main memory candidate
- Explored emerging NVM technologies in order to find their appropriate position in the memory hierarchy using range of target applications (Featured in Intel Technology Journal - 2013)
- Accurate Memory Simulations
- Designed set of techniques, when applied in a full-system simulator give reliable, accurate and less variable results
- Our techniques implemented on MARSSx86 integrated with DRAMSim2
for case study to show reduce variability in simulations
Work Experience
- Research Scientist, Intel Labs, Bangalore (Dec 2015 - April 2022), Hillsboro (May 2022 - present)
- Scalable Vector Search: optimizing approximate nearest neigbor search on Intel hardware.
- Architecture research on emerging applications like Deep Learning
- Research on micro-architecture: NVM based LLC, Memory bandwidth efficiency and core resource partitioning algorithm
- Senior Hardware Engineer, Oracle (formerly SUN Microsystem), Santa Clara (June 2014 - December 2015)
- Worked on performance modeling, projection and design space exploration of SPARC processor
- Responsible for modeling and maintaining memory-controller and database-accelerator modules
- Architectural explorations for future processors and debugging performance issues during bring-up
- Research Assistant, Memory Systems Research Lab, Dept. of ECE, University of Maryland (Sep 2010 - May 2014)
- DRAM low power modes and refresh mechanisms
- Novel applications of persistent memory
- Reliable full-system simulation infrastructure
- Graduate Intern, Intel Corporation, Hillsboro, USA ( June 2013 - August 2013)
- Quantified speed versus accuracy tradeoffs in memory modelling at several levels of abstraction (constant, analytical, queue-based, detailed etc.)
- Implemented and integrated a memory model, which is 10x faster than the cycle accurate DRAMSim2 and is within 10% of accuracy
- Technical Mentor: Emily Shriver, Strategic CAD Labs (SCL)
- Senior ASIC Engineer, LSI Corporation, India (Jan 2009 - July 2010)
- RTL design and verification of DDR2/3 Memory Agent and DDR PHY
- Architecture of DDR3 training sequence and write leveling algorithm
- Implementation of SystemVerilog and VMM based automated testbench
- ASIC Design and Verification Engineer, Nevis Networks Pvt. Ltd., India (July 2005 - June 2006, May 2007-Jan 2009)
- Verification of DRAM Control module in a 96-core Network Processor
- SystemC modeling and Full Chip Verification environment integration
- Prototyping of memory controller on Xilinx's Vertex-4 based FPGA board
- Design Engineer, STMicroelectronics , India (June 2006 - May 2007)
- Modelling and design of Wireless USB Medium Access Control (MAC) Chip modules
- Summer Intern, KNU, Daegu , South Korea (May 2004 - July 2004)
- Worked on speech enhancements and implemented Dynamic Time Warping (DTW) on TI-DSK 6711 using Simulink
Selected Publications
- Mariano Tepper, Ishwar Singh Bhati, Cecilia Aguerrebere, Mark Hildebrand, Ted Willke,
"LeanVec: Search your vectors faster by making them fit",
Transactions on Machine Learning Research(TMLR), 2024.
- Cecilia Aguerrebere, Mark Hildebrand, Ishwar Singh Bhati, Theodore Willke, Mariano Tepper,
"Locally-Adaptive Quantization for Streaming Vector Search",
arXiv, 2024.
- Cecilia Aguerrebere, Ishwar Bhati, Mark Hildebrand, Mariano Tepper, Ted Willke,
"Similarity search in the blink of an eye with compressed indices",
Proceedings of the VLDB Endowment, 2023.
- Ishwar Bhati, Udit Dhawan, Jayesh Gaur, Sreenivas Subramoney, and Hong Wang,
"MARS: Memory Aware Reordered Source", arXiv:1808.03518, August 2018.
- Kunal Korgaonkar, Ishwar Bhati, Huichu Liu, Jayesh Gaur, Sasikanth Manipatruni, Sreenivas Subramoney, Tanay Karnik, Steven Swanson, Ian A. Young, and Hong Wang,
"Density Tradeoffs of Non-Volatile Memory as a Replacement for SRAM based Last Level Cache", [Slides]
" Proc. 45th International Symposium on Computer Architecture (ISCA 2018), Los Angeles, CA, June 2018.
- Kaushik Vaidyanathan, Daniel H Morris, Uygar E Avci, Ishwar S. Bhati, Lavanya Subramanian, Jayesh Gaur, Huichu Liu, Sreenivas Subramoney, Tanay Karnik, Hong Wang, and Ian A Young,
"Overcoming interconnect scaling challenges using novel process and design solutions to improve both high-speed and low-power computing modes",
" Electron Devices Meeting (IEDM), 2017 IEEE International.
- Ishwar Bhati, Mu-Tien Chang , Zeshan Chishti, Shih-Lien Lu, and Bruce Jacob,
"DRAM Refresh Mechanisms, Penalties, and Trade-Offs", IEEE Transactions on Computers, vol. 65, no. 1, pp. 108-121. January 2016.
- Ishwar Bhati, Zeshan Chishti, Shih-Lien Lu, and Bruce Jacob,
"Flexible auto-refresh: Enabling scalable and energy efficient
DRAM refresh reductions,",
" Proc. 42nd International Symposium on Computer Architecture (ISCA 2015). . Portland, OR, June 2015.
- Ishwar Bhati, Zeshan Chishti, and Bruce Jacob,
"Coordinated refresh: Energy efficient techniques for DRAM refresh scheduling",
Proc. 2013 International Symposium on Low Power Electronics and Design (ISLPED 2013). Beijing China, September 2013.
- Jim Stevens, Paul Tschirhart, Mu-Tien Chang, Ishwar Bhati, Peter Enns, James Greensky, Zeshan Chishti, Shih-Lien Lu, and Bruce Jacob, "An Integrated Simulation Infrastructure for the Entire Memory Hierarchy: Cache, DRAM, Nonvolatile Memory, and Disk,", Intel Technology Journal (ITJ), vol. 17, no. 1, 2013.
Ph.D. Thesis
Patents
- Maria Cecilia Aguerrebere Otegui, Ishwar Bhati, Mark Hildebrand, Mariano Tepper, Theodore Willke,
"Locally-adaptive vector quantization for similarity search", US Patent application filed, 2024
- Supratim Pal, Sasikanth Avancha, Ishwar Bhati, Wei-Yu Chen, Dipankar Das, Ashutosh Garg, Chandra S Gurram, Junjie Gu, Guei-Yuan Lueh, Subramaniam Maiyuran, Jorge E Parra, Sudarshan Srinivasan, Varghese George,
"Instructions and logic for vector multiply add with zero skipping", US Patent granted, 2023
- Ishwar S Bhati, Udit Dhawan, Jayesh Gaur, Sreenivas Subramoney,
"Memory aware reordered source", US Patent granted, 2020
- Ishwar S Bhati, Huichu Liu, Jayesh Gaur, Kunal Korgaonkar, Sasikanth Manipatruni, Sreenivas Subramoney, Tanay Karnik, Hong Wang, Ian A Young,
"Write congestion aware bypass for non-volatile memory, last level cache (LLC)", US Patent granted, 2019
- Kunal Kishore Korgaonkar, Ishwar S Bhati, Huichu Liu, Jayesh Gaur, Sasikanth Manipatruni, Sreenivas Subramoney, Tanay Karnik, Hong Wang, Ian A Young,
"Method and apparatus for reducing write congestion in non-volatile memory based last level caches", US Patent granted, 2018
- Ishwar Bhati, Zeshan Chishti and Shih-Lein L. Lu,
"Techniques to Reduce Memory Cell Refreshes for a Memory Device", US patent granted, 2016
- Ishwar Bhati and Zeshan Chishti,
"Coordinating Power Mode Switching and Refresh Operations in a Memory Device", US Patent granted, 2015
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