Hi, I'm Stefanos Baziotis

PhD Candidate

University of Illinois at Urbana-Champaign
Department of Computer Science

Email: sb54@illinois.edu
Room 4103, Siebel Center
Research Interests
  • Compilers
  • Data Management Systems
  • Performance Engineering
  • Programming Languages
  • Distributed Systems

I am a third-year CS PhD candidate, at the University of Illinois Urbana-Champaign (UIUC), in the Dept. of Computer Science (CS). My advisor is Prof. Charith Mendis. I also work closely with Daniel Kang.

I'm doing research at the intersection of compilers and data management systems. More broadly, my interests extend to performance engineering, programming languages, and distributed systems.

Before coming to UIUC, I worked as a compiler researcher at NEC and I was also involved with the Liberty Research Group from Princeton. I obtained my B.Sc. from the Department of Informatics, University of Athens, where I did my thesis with Prof. Yannis Smaragdakis.



May 20, 2024 I started my internship at Microsoft Research, working with Tarique Siddiqui and Christian König.
Nov 20, 2023 Dias got accepted at SIGMOD 2024. The code is public and you can also try Dias using our Colab notebook.
Nov 11, 2023 New article: Inverting the Inverted: Revisiting Dismissed Ideas in Research.



  • Dias: Dynamic Rewriting of Pandas Code
    Stefanos Baziotis, Daniel Kang, Charith Mendis
    Accepted at SIGMOD 2024
      author = {Baziotis, Stefanos and Kang, Daniel and Mendis, Charith},
      title = {Dias: Dynamic Rewriting of Pandas Code},
      year = {2024},
      issue_date = {February 2024},
      publisher = {Association for Computing Machinery},
      address = {New York, NY, USA},
      volume = {2},
      number = {1},
      url = {https://doi.org/10.1145/3639313},
      doi = {10.1145/3639313},
      abstract = {In recent years, dataframe libraries, such as pandas have exploded in popularity. Due to their flexibility, they are increasingly used in ad-hoc exploratory data analysis (EDA) workloads. These workloads are diverse, including custom functions which can span libraries or be written in pure Python. The majority of systems available to accelerate EDA workloads focus on bulk-parallel workloads, which contain vastly different computational patterns, typically within a single library. As a result, they can introduce excessive overheads for ad-hoc EDA workloads due to their expensive optimization techniques. Instead, we identify source-to-source, external program rewriting as a lightweight technique which can optimize across representations, and offer substantial speedups while also avoiding slowdowns. We implemented Dias, which rewrites notebook cells to be more efficient for ad-hoc EDA workloads. We develop techniques for efficient rewrites in Dias, including checking the preconditions under which rewrites are correct, dynamically, at fine-grained program points. We show that Dias can rewrite individual cells to be 57\texttimes{} faster compared to pandas and 1909\texttimes{} faster compared to optimized systems such as modin. Furthermore, Dias can accelerate whole notebooks by up to 3.6\texttimes{} compared to pandas and 27.1\texttimes{} compared to modin.},
      journal = {Proc. ACM Manag. Data},
      month = {mar},
      articleno = {58},
      numpages = {27},
      keywords = {cross-representation, dynamic, pandas, rewriting}

    Copy bibtex







  • Latest Advancements in Automatic Vectorization Research
    Stefanos Baziotis
    LLVM-CGO 2021
  • Introduction to (Unconventional) Vectorization
    Stefanos Baziotis
    LLVM Social Bangalore, December 2020
  • Εισαγωγή στο Google Summer of Code (Updated)
    Stefanos Baziotis
    University of Athens, Department of Informatics, Operating Systems Course 2020
  • The Present and Future of Interprocedural Optimization in LLVM
    Luofan Chen, Kuter Dinel, Shinji Okumura, Hideto Ueno, Johannes Doerfert, Stefanos Baziotis
    LLVM Developers' Meeting 2020
  • A Deep Dive into the Interprocedural Optimization Infrastructure
    Luofan Chen, Kuter Dinel, Shinji Okumura, Hideto Ueno, Johannes Doerfert, Stefanos Baziotis
    LLVM Developers' Meeting 2020
  • Finding Your Way Around the LLVM Dependence Analysis Zoo
    Stefanos Baziotis, Simon Moll
    LLVM Developers' Meeting 2020
  • Εισαγωγή στο Google Summer of Code
    Stefanos Baziotis
    ACM UoA Student Chapter, February 2020
  • Εισαγωγή στο Open Source Software
    Stefanos Baziotis
    ACM UoA Student Chapter, November 2019