Zixuan Wang

Graduate Research Assistant
  • Computer Science and Engineering
  • University of California, San Diego

Summary

I am Zixuan Wang (王子轩), a Ph.D. student at University of California San Diego. I'm working with Prof. Jishen Zhao, and my research is mainly on memory systems. I'm also working with Prof. Steven Swanson at NVSL Lab, UCSD.

My research spans computer architecture and operating system (IEEE Micro TopPicks'21, MICRO'20, ArXiV'19), machine learning (HPCA'22, ATC'21), programming language/library (ATC'21) and security.

I'm also actively participating in open source projects. I have contributed 13 patches to Linux KVM community. I developed and am maintaining multiple open source projects on GitHub. These projects have received more than 1,400 stars and impacted ~100,000 users (79K + 14K + ...).

I got my Bachelor's degree from Zhejiang University, China, where I worked with Prof. Wenzhi Chen and Prof. Qingsong Shi on architecture and operating system, at Computer Architecture Lab.

I take photos (my photo gallery). I've got a Guinness Record by participating the world's largest line dance. I play table tennis and badminton. I also play games on PC, Switch, PS4 and PS5. I enjoy playing my 3D Printer. I built a rack in my closet.

And check out my kitten, Inu.

Experience

Graduate Research Assistant

University of California, San Diego
2018 - Present

I'm working in STABLE Lab and NVSL Lab, doing research on arch and system design for memory, recent works include:

  • LENS: a profiler that discovers NVRAM DIMM micro-architecture design.
  • VANS: a cycle-level NVRAM simulator that matches the real products' performance.
  • Ayudante: a learning-based persistent memory automatic programming framework.

Software Engineering Intern

Google
2021 June - 2021 Sept

I developed UEFI and AMD SEV/SEV-ES supports for KVM-Unit-Tests. Patch sets are posted to the KVM mailing list:

I received two peer bonuces during this internship.

Submission Co-Chair

MICRO 2021
2021 Mar - July

I served as submission co-chair in MICRO 2021, worked with program chairs to manage submissions and organize the TPC meeting. I also open-sourced MightyPC , a toolkit I built to manage conference submissions.

Research Intern

SOLAB, SK hynix America
2019 June - Sept

We evaluated performance of the GEN-Z memory prototype, and enabled GPU direct access to GEN-Z memory.

Undergraduate Research Assistant

Zhejiang University, China
2015 - 2018

I worked in Computer Architecture Lab, did research on operating system and computer architecture:

  • We developed ZJUNIX operating system from scratch, and run it on ZJU-SoC, which is a self-implemented MIPS SoC on FPGA.
  • We also developed an FPGA accelerator for High-Frquency Trading.
  • Another cool project is Portable Modulized 3D Bioprinter, which earned Outstanding Prize on Challenge Cup.

Publication

Enabling Efficient Large-Scale Deep Learning Training with Cache Coherent Disaggregated Memory Systems

HPCA22
Zixuan Wang, Joonseop Sim, Euicheol Lim, Jishen Zhao

Ayudante: A Deep Reinforcement Learning Approach to Assist Persistent Memory Programming

ATC21
Hanxian Huang, Zixuan Wang, Juno Kim, Steven Swanson, Jishen Zhao

Enabling Fast Recovery for Autonomous Vehicle Systems with Linux Container Checkpointing

SOSP21 SRC
Maximilian Apodaca, Shengye Wang, Zixuan Wang, Jishen Zhao

Basic Performance Measurements of the Intel Optane DC Persistent Memory Module

ArXiV
Joseph Izraelevitz, Jian Yang, Lu Zhang, Juno Kim, Xiao Liu, Amirsaman Memaripour, Yun Joon Soh, Zixuan Wang, Yi Xu, Subramanya R. Dulloor, Jishen Zhao, Steven Swanson

Reliable and Flexible Large Scale Memory Network

NVMW19
Zixuan Wang, Xiao Liu, Jongryool Kim, Hokyoon Lee, Jishen Zhao

A Modulized Portable 3D Bioprinter

Utility model patent, China
Zixuan Wang, Bin Zhang, Wenzheng Kuang, Huayong Yang

Teaching

Hardware Based Computer System Comprehensive Practice

Zhejiang University
Teaching Assistant, 2018

Help students to develop their own SoC (on FPGA) to support their OS.

Operating System

Zhejiang University
Teaching Assistant, 2017

Help students to develop their own operating system from scratch.

Projects

2021 Google summer internship project.
  • C
  • x86 Assembly
  • x86 Bootstrap
  • KVM
  • SeaBIOS
  • UEFI
  • AMD SEV
  • AMD SEV-ES
  • GNU Toolchain
  • Linker Script

We are one of the first to build UEFI and AMD SEV/SEV-ES support in KVM-unit-tests, a widely-adopted KVM testing framework:

  • Implement UEFI support as an alternative to the existing SeaBIOS+Multiboot solution.
  • Implement AMD SEV and SEV-ES support
  • Source code
MICRO 2020 paper: Characterizing and Modeling Non-Volatile Memory Systems.
  • C
  • Linux Kernel
  • x86 Assembly

We build the first profiler that can discover the non-volatile memory on-DIMM micro-architecture.

  • LENS runs in Linux kernel space.
  • Micro-benchamrks are written in x86 assembly.
  • LENS discovers the complex micro-architecture design of NVRAM DIMM products.
  • Source code
MICRO 2020 paper: Characterizing and Modeling Non-Volatile Memory Systems.
  • C++ 17
  • Python
  • R
  • Cycle Accurate Simulation

We build a cycle-level NVRAM simulator and validate its performance with Intel Optane Persistent Memory, the first commercially available NVRAM product.

  • VANS takes advantage of modern C++ features to simplify the code and increase the simulation performance.
  • VANS performance matches the real NVRAM products.
  • Automated testing for VANS prcision.
  • Source code
Work done during SK Hynix internship.
  • FGPA
  • GPU
  • Linux

We evaluated the GEN-Z memory prototype, and developed a framework for GPU to directly access GEN-Z memory through PCIe.

  • cuDF library runs 16x faster compared to indirect access through CPU.
Deployed in production environment.
  • FGPA
  • Linux
  • Userspace IO
  • MIPS Assembly

A FPGA accelerator for high-frequency trading. We offload the decision procedure to FPGA, and forward incomming network data directly to FPGA. In this way, trading data doesn't go through NIC, PCIe, CPU, Main Memory to make a decision.

  • Use FPGA to accelerate network response and decision making.
  • Use 10-Gigabit Ethernet for communication between FPGA and PC.
A micro:bit emulator based on QEMU.
  • C
  • ARM Assembly
  • ARM Mbed OS
  • Bootloader

micro:bit is a development board for students' programming training. It has a ARM Cortex-M0 processor, as well as many peripherals. But micro:bit developers need an emulator to help them debug the low-level code, so we made it on QEMU.

Develop:

  • Implement Cortex-M0 features from QEMU's original Cortex-M3 emulator.
  • Implement peripheral emulators, e.g LED matrix, timer, clock generator, random number generator, etc.
  • Organize CPU Virtual Address Space with regard to micro:bit's spec.
  • Disassemble and reverse engineered micro:bit's Bootloader.
  • Go through ARM Mbed OS to make sure hardware emulation is correct.
  • Debug with QEMU and remote GDB, on assembly code level.

Result:

  • It can run unmodified micro:bit example code, written in C, Python or JavaScript.
  • Outstanding graduation thesis of computer science department, Zhejiang University, 2018.
  • Source code
Self-designed OS running on self-designed SoC.
  • Open Source
  • OS Design
  • Bootloader
  • C
  • MIPS Asm
  • Linker Script

A self-designed OS from groud up, running on self-designed SoC or QEMU. We also implement the corresponding bootloader. This project serves as a sample for OS courses in Zhejiang University.

  • Bootloader to load kernel from filesystem.
  • Interrupt and exception.
  • Buddy + Slab memory management.
  • Process scheduling.
  • Userspace programs: shell, ls, ps...
  • FAT and ext2 filesystem.

ZJU-SoC

Dec. 2016
Self-designed SoC on FPGA.
  • Open Source
  • FPGA
  • Verilog

A self-designed SoC from groud up. It can run ZJUNIX as well as Arduino programs. This project serves as a sample for OS courses and Computer Hardware System courses in Zhejiang University.

  • Self-implemented 5 stage pipline MIPS32 CPU on FPGA, 93 instructions, 2 level cache.
  • With 512M DDR3, VGA, PS2, SD controller.
  • Capable of running ZJUNIX Operating System.
  • Capable of running Arduino programs, with our implementation of Arduino library.
  • Teamwork with 2 other undergraduates.
Printing tissue directly on wounds; It fits in a 28-inch travel case.
  • Image Processing
  • Mechanical Design
  • Real-time System
  • FPGA

A portable modulized 3D bioprinter that prints tissue directly on wounds. The whole device fits in a 28-inch travel case, and can be assembled in several minutes.

  • Using FPGA accelerated edge detector to fulfill the real-time computing.
  • Utility model patent, 201720246090.1
  • The outstanding prize of Challenge Cup, Zhejiang Province.
  • Top 10 Academic Projects, Zhejiang University, 2017
  • Teamwork with 8 other undergraduates.
A FPGA acceleartion of PCISPH fluit simulation.
  • Computer Graphics
  • FPGA
  • FPGA for calculation, PC for rendering.
  • FPGA communicates with PC through ethernet.
  • The second prize of Digilent Design Contest, 2017 China

For Fun

The first GNU linker script highlight extension for VS Code, based on TmLanguage (over 70K installations)
  • VS Code Extension
  • Yaml
  • Linker Script

ZJU Thesis

May. 2018
LaTeX template for Zhejiang University graduate design and thesis (over 600 stars)
  • LaTeX
  • LaTeX template, widely used by students at Zhejiang University
  • Recommended by School of Undergraduates.

Makefile Templates

July. 2017
Some makefile templates for C/C++ projects. Over 300 stars.
  • Makefile
A Chinese IM written in pure MIPS assembly.
  • MIPS Assembly
  • Keyboard Interrupt
  • VGA Display
  • A Chinese pinyin IM written in pure MIPS assembly, ~2000 lines of code.
  • It captures keyboard input, decodes english characters into pinyin, then queries the GB2312 database to find a corresponding Chinese character.
  • Demo picture. (The code is lost though.)
A simple compiler for Tiger, a functional programming language.
  • Bison
  • Flex
  • C++ 11/14
  • Lexical analysis
  • Syntax analysis
  • Abstract syntax tree
  • Intermediate code generator

Education

  • PhD student in CS
    UC San Diego
    2018 - Present
  • BS in CS
    Zhejiang University
    2014 - 2018

Awards

  • IEEE Micro Top Picks
    Annually awarded to 10~12 best computer architecture papers published in the past year, 2021
  • Google Peer Bonus
    Awarded by peer Googlers recognizing my excelent work. Got two peer bonuses during my summer internship, Google 2021
  • Outstanding Grad Thesis
    Outstanding graduation thesis among cs department, Zhejiang University, 2018
  • Annual Outstanding Student
    Top 10 outstanding students among cs department, including grad and undergrad students, Zhejiang University, 2017
  • Outstanding Prize
    Top 10 academic projects, Challenge Cup, National Undergraduate Curricular Academic Science and Technology Works Competition, Zhejiang Province China, 2017
  • Academic Star
    Top 1% student on academic area among cs department, Zhejiang University, 2017
  • Top 10 Academic Projects
    Our portable modulized 3D bioprinter won top 10 academic projects prize, Zhejiang University, 2017
  • DDC 2nd Prize
    Digilent Design Contest, China, 2017
  • 3rd Prize
    Advanced Computer Architecture Undergraduate Innovation Competition, CCF China, 2016

Skills & Tools

Programming Language

  • C/C++
  • Python
  • R
  • x86/ARM/MIPS Assembly
  • Go
  • Java
  • Java Script
  • Verilog
  • CUDA

Technologies

  • Linux Kernel
  • KVM
  • Persistent Memroy
  • AMD SEV/SEV-ES
  • UEFI
  • SeaBIOS
  • Virtualization
  • Microarchitecture Security
  • QEMU
  • GEM5
  • FPGA
  • MIPS Arch
  • ARM Mbed OS
  • MongoDB
  • InfluxDB
  • Grafana
  • Tensorflow

Skills

  • Performance Profiling
  • x86 Bootstrapping
  • Microarchitecture Reverse Engineering
  • Side/Covert Channel Attack
  • Trusted Execution