Dhananjay Singh Email and Phone Number

Engineering at Oracle Cloud Infrastructure

• Converted several centrally important Cloud Formation Stacks to be deployed using AWS CDK(Cloud Development Kit) instead of Cloud Formation Templates (CFTs)• Created and deployed SNS, SQS, DynamoDB tables, lambda, API Gateway, IAM roles, and policies by making CI/CD pipelines that deploy to the testing, staging, and production environments• Worked on automating the entire dev set up for new developers, including containerizing many main apps, databases, and services using Docker and shell scripting, and setting up the environment with all the required tools, software, profiles, permissions, etc. Provided extensive help with troubleshooting and making on the fly bug fixes• Made a program that scans the entire database and defines all the relations between entities, thereby helping make crucial decisions regarding server migration strategies.

- Evaluated the performance increase while using large page sizes (superpages) in Translation Lookaside Buffers (TLBs) for large-memory workloads- Used QEMU to boot an arm64 FreeBSD VM and modified its kernel to create superpage mappings- Learned that TLB misses, due to low TLB coverage, degrade performance in large-memory applications by up to 30% - 60%- Implemented new page mapping routines (in C) to enable creation, promotion, demotion, and removal of 4KB base pages, 64KB superpages, and 2MB superpages, so as to boost TLB coverage- Tested that new page mapping routines work using system calls and checking the page tables

- TA for COMP 321 - Introduction to Computer Systems- Assisted the professor with grading homework projects- Held weekly office hours to answer conceptual questions and help debug code for up to 3 hours at a time

- Worked with the Billing and Tools team- Made performance optimizations to billing details processing and loading - Implemented parallelism for the load job and set up a two-level DynamoDB caching mechanism (incl. associated AWS CloudFormation set up)- Made performance optimizations of 32x, 50x, and 15x for three main components of the billing data- Gained experience with back-end Java, rest APIs, AWS (S3, CloudFormation stacks and templates, IAM roles and policies, DynamoDB, EC2, AWSCLI), CI/CD pipelines, dev/prod/staging environments, scrum and git

- Helped students with lab assignments- Provided help with hardware/software set up and debugging code- Troubleshooted hardware and software issues