Posts on Tristan Rice

rdma4py: Do We Need Transfer Engines for PyTorch and RDMA?

Tue, 21 Jul 2026 00:00:00 -0700

Originally published on the PyTorch Developer Log.

TL;DR - Python can drive GPUDirect RDMA at line rate without a large transfer-engine abstraction. rdma4py provides lightweight, backend-specific bindings for ibverbs, AWS EFA, and NVMe-oF, reaching about 400 gbps in our benchmarks while preserving direct access to the underlying APIs.

Introduction

Recently, quite a few different “transfer engines” have been developed for fast weight synchronization between machines using RDMA-capable transports and libraries such as NVLink, ibverbs, EFA, NVMe-oF, and SPDK. These include projects such as Mooncake, NIXL, and Uniflow. As with any large project and abstraction, these projects make trade-offs around specific use cases that might not be optimal for yours.

Python First Comms for Researchers

Thu, 14 May 2026 00:00:00 -0700

Originally published on the PyTorch Developer Log.

TL;DR – Modifying the C++ comms layer is a big barrier when researchers want to prototype new collective features. We’ve added Python bindings to torchcomms (#2080) and built two pure-Python backend prototypes — one wrapping NVIDIA’s new nccl4py bindings (#2515) and one built on SymmetricMemory + Triton (#2521) — both passing the core torchcomms integration test suite. Since they plug into torch.distributed, researchers can fork, tweak, and mix them with existing projects like TorchTitan without touching C++.

torchcomms: a modern PyTorch communications API

Wed, 22 Oct 2025 00:00:00 -0700

Originally published on the PyTorch Blog.

Introduction

Torchcomms is a new experimental, lightweight communication API intended for use with PyTorch Distributed (PTD). In addition to the core API, we are open-sourcing NCCLX, a new backend we developed to scale to over 100,000 GPUs.

With our first release of torchcomms, we’re delivering the foundational APIs and backends required for large-scale model training in PyTorch. This initial release focuses on core communication primitives that enable reliable and performant distributed training at scale. Over the next year, we’ll continue to mature the offering—introducing features that make it easier to prototype new collectives, scale seamlessly with built-in fault tolerance, and optimize device-centric communication patterns. Our roadmap is focused on empowering researchers and developers to move faster, test new ideas at scale, and build the next generation of large-scale AI systems.

Fault Tolerant Llama: training with 2000 synthetic failures every ~15 seconds and no checkpoints on Crusoe L40S

Fri, 20 Jun 2025 00:00:00 -0700

Originally published on the PyTorch Blog.

Collaborators: Less Wright, Howard Huang, Chien-Chin Huang, Crusoe: Martin Cala, Ethan Petersen

tl;dr: we used torchft and torchtitan to train a model in a real-world environment with extreme synthetic failure rates to prove reliability and correctness of fault tolerant training

Training loss across 1200 failures with no checkpoints.

NOTE: Each small spike is a non-participating worker recovering which affects the metrics but not the model

Introduction

We want to demonstrate torchft in worst case scenarios by running a training job with the most extreme failure rates possible.

torchdrive: Open Source + Nuscenes Support

Fri, 06 Oct 2023 21:01:23 -0700

Over the past 9 months, I’ve been rewriting my models from the ground up and open sourcing them on GitHub. The code is now fully public and available for anyone to use and modify.

The majority of the code is a BSD-3-Clause license which matches other open source projects such as PyTorch. There are a few pieces with modules borrowed from other projects.

This is a follow up to 3D Dynamic Objects and is part of a series where I try to train models to perform common self driving tasks from scratch.

3D Dynamic Objects - DIY Self Driving Part 5

Sat, 21 Jan 2023 13:51:43 -0800

This is a follow up to 3D Semantic Segmentation and is part of a series where I try to train models to perform common self driving tasks from scratch.

I decided to switch areas of focus for this new model. Previously I had been working entirely with dense models which output dense representations about the world such as the voxel occupancy grids and the BEV semantic maps for lane lines and drivable space.

3D Semantic Segmentation - DIY Self Driving Part 4

Tue, 08 Nov 2022 20:28:04 -0800

This is a follow up to Voxel from Multicam and is part of a series where I try to train models to perform common self driving tasks from scratch.

I’ve previously put together occupancy models for self driving but that’s only one specific perception task.

Another common driving task is semantic segmentation. Semantic segmentation takes in the image and for every pixel predicts a specific class. This can be used to tell things like walls apart from cars or classify different types of lane lines and curbs on a road.

Voxel from Multicam - DIY Self Driving Part 3

Sun, 12 Jun 2022 14:37:27 -0700

This is a follow up to Monocular Depth Improvements and is part of a series where I try to train models to perform common self driving tasks from scratch.

Background

I spent a couple of months optimizing single camera (monocular) depth models before realizing that maybe there’s a better way. One of the biggest improvements I made to the monocular models was adding a 3D geometric constraint to enforce that the model didn’t predict depths below the ground.

Monocular Depth Improvements - DIY Self Driving Part 2

Sun, 12 Jun 2022 14:20:04 -0700

This is a follow up to DIY Self Driving.

In the past few months I’ve been iterating on my previous work on creating self driving models. The main goals were initially:

train depth models for each camera
generate joint point clouds from the multiple cameras
use the fused outputs to create a high quality reconstruction that I can use to label things like lane lines

This post lists all the various problems I ran into and some of the mitigations I applied for those issues.

DIY Self Driving - A Holiday Side Project

Mon, 10 Jan 2022 20:23:09 -0800

This work was done in collaboration with green, Sherman and Sid.

During the holidays I decided to take some time and try to make my own self driving machine learning models as part of a pipe dream to have an open source self driving car. I hacked this together over the course of about 2 weeks in between holiday activities.

Disclaimer 1: I’m a software engineer on PyTorch but this work was done on my own time and not part of my normal duties.

Hacking my Tesla Model 3 - Software Modes

Tue, 26 May 2020 20:34:09 -0700

This is a follow up to Hacking my Tesla Model 3 - Internal API.

As part of reverse engineering the Tesla Model 3 internals, I’ve been running a subset of the CID car services to see how they work.

The car computers are using Intel Atom based processors so it’s easy to setup a chroot to launch the services.

I’ve written two helper scripts to set up the car environment:

chroot.sh - runs a command in the Tesla chroot environment.
start_car.sh - runs the main vehicle services: escalator, ecall_client, sim_service, carserver, vehicle. Other services can be launched via ./chroot.sh /usr/tesla/UI/RunQtCar <service>

These scripts assume a CID image is extracted at squashfs-root/.

Hacking my Tesla Model 3 - Internal API

Tue, 26 May 2020 07:34:34 -0700

This is a follow up to Hacking my Tesla Model 3 - Security Overview.

This is a technical description of all the internal services I’ve found and notes about how they work.

All of these services described are normally unaccessible due to seceth and firewall rules.

Hosts

192.168.90.100 cid ice
192.168.90.100 ic
192.168.90.102 gw
192.168.90.103 ap ape
192.168.90.104 lb
192.168.90.105 ap-b ape-b
192.168.90.30 tuner
192.168.90.60 modem

Tuner isn’t present on newer Model 3s as the AM/FM radio has been removed. I’m not sure what lb is.

Hacking my Tesla Model 3 - Security Overview

Tue, 12 May 2020 23:12:03 -0700

See the follow up at Hacking my Tesla Model 3 - Internal API.

I recently got a Tesla Model 3 and since I’m a huge nerd I’ve been spending a lot of time poking at the systems and trying to reverse engineer/figure out how to root my car.

I work on Machine Learning infrastructure so I’d love to be able to take a deep look at how autopilot/FSD works under the hood and what it can actually do beyond what limited information the UI shows. I know some people have managed to get a copy of this.

Cracking Dropbike: Data Breach and Free Bike Rides

Wed, 19 Sep 2018 16:24:45 -0700

Edit 2018-09-20T15:42-07:00: Dropbike’s response to these issues

Edit 2018-09-19T19:38-07:00: Updated support comments to more accurately reflect their response.

Note: These issues were responsible disclosed and have since been fixed. This is my understanding of the issues to the best of my knowledge.

To give you a little bit of background, Dropbike is a new bike sharing service that just launched at the University of British Columbia as one of their first locations. They’re only about a year old and based out of Toronto. The service is pretty simple, they have a bunch of bikes with a cell connection and bluetooth low energy locks spread out all over campus. You can use their app to find nearby bikes and unlock them. Overall, it seems like a neat convenient service and I was super excited to have them on campus.

Running Untrusted Code in a Secure Docker Container from Scratch

Thu, 10 May 2018 16:18:25 -0700

As part of Luk.ai we need to be able to run Tensorflow within a secure environment since a running Tensorflow model can do pretty much anything it wants to the host system.

For ease of deployment, we’d also like to be able to use Docker since it provides nice sandboxing support and ability to limit resources used by the container. We’d also like for the container to not be able to do anything other than run models. Thus, we needed a completely stripped down container with no permissions set. It’s also pretty nice if it’s as small as possible.

nwHacks Machine Learning

Sat, 08 Jul 2017 00:34:19 -0700

I’ve been doing a bunch of work during my internship with Machine Learning models so I figured I take a crack at applying them to some of my personal projects. Just for fun I wanted to see what would happen if I tried to train a model on the registration, check-in and submission data for nwHacks.

I decided to use Hector, a suite of algorithms completely written in Go since that’s what most of the nwHacks tooling is written in. Took a few hours to write a pipeline that would read in the nwHacks registration data from Firebase and output it into a format that Hector supports.

UBC Food Safety

Fri, 21 Apr 2017 20:20:58 -0700

A couple of my friends got food poisoning eating at places in the village in the past month or so. I decided to do some digging and find out which places have the best food safety records. To my horror, pretty much every place has food safety violations on campus.

nwHacks 2017 Tech Stack

Fri, 17 Mar 2017 19:19:15 -0700

With nwHacks 2017 coming up this weekend I figured it would be a good time to do a writeup of the tech stack and all the different components that are used to make the hackathon a success. This covers all of the different components of the stack and what technologies were used.

Shadow Hunters: Roll Probabilities

Tue, 08 Nov 2016 02:45:00 +0000

This contains a list of all the probabilities you might be interested in when playing the Shadow Hunters board game.

Hugo: Multiple List Views and Grids

Thu, 03 Nov 2016 20:11:16 +0000

Yesterday, I decided to take a shot at rewriting the University of British Columbia’s Technical Career Fair (UBC TCF) website in Hugo. The TCF is one of the many events that the UBC Computer Science Student Society puts on every year and there’s been a day-of website for a number of years to allow companies to find their booths and students to find out about the companies.

The old site was written in a combination of Django and Python and had a small admin interface. Nothing about it really required to to be dynamic, other than the interface for adding new companies. I figured it’d be way simpler to just have every company be represented as a “post” in Hugo.

Test Of Features

Wed, 02 Nov 2016 02:13:04 +0000

I’ve been doing a bunch of work on this site. This is a test page for all the different visual elements.

Block Quote Example

Hey there! This is some example text that I needed to add to correctly get this line to wrap. How do you guys feel about the color blue?

Syntax Highlighting Example

Here’s an example “Hello World!” Go program. I tend to prefer log over fmt when it comes to printing things to the screen.

Calendar

Tue, 01 Nov 2016 21:54:17 +0000

This is my weekly calendar. I’m typically available any time Monday to Friday 9:00 to 17:00 unless listed as busy below.

New Site

Fri, 14 Oct 2016 19:48:54 +0000

This is the new site. Pretty bare bones right now.

Koans of Jins

Wed, 24 Aug 2016 20:49:48 +0000

“Fixing it is not the battle; finding it is.”
“It only takes one line to completely break things.”
“Make love not muffins.”
“No pineapples.”
“Taxis are mean.”
“Better to binge on oranges than […] crack.”
“I only speak the truth.”
“Crêpes can’t save you from eternal damnation.”
“The drain smells like a drain.”

Microwave

Thu, 08 Oct 2015 05:24:18 +0000

Lightning Storm

Thu, 13 Aug 2015 05:25:00 +0000

There’s a pretty awesome lightning storm going on outside.

New Site

Thu, 13 Aug 2015 05:23:37 +0000

I’ve done a complete rewrite of the site using Polymer. It was pretty quick to write and has some neat features such as this embedded blog backed by tumblr. You can see the old blog at http://blog.fn.lc .

It also does live fetches of my most popular GitHub projects.

Both of these are implemented by directly accessing the respective APIs using iron-ajax.

Fic Recommend

Tue, 11 Aug 2015 21:20:41 +0000

https://fn.lc/ficrecommend/

I launched this today as it’s become fairly polished under my own personal use.

The ranking algorithm is pretty simple but actually works fairly well.

Here’s how it works:

Gets a story in the form of a URL
Look up all the users who have liked/favorited that story.
Count all the favorited stories of those users.
Display the top 50 stories by number of favorites.

Source Code: https://github.com/d4l3k/ficrecommend

messagediff

Tue, 11 Aug 2015 21:15:38 +0000

A library for doing diffs of arbitrary Golang structs.

https://github.com/d4l3k/messagediff\

I put this together because I wanted an easy way to display diffs during testing. It’s fairly similar to an internal library I used during my internship this summer.

It’s pretty basic but I’m planning on adding LCS support if I ever get around to it. It does have support for diffing non-exported fields using go-spew’s unsafe reflect modifications.

i18n-js with sinatra-asset-pipeline

Thu, 18 Dec 2014 02:16:00 +0000

I just implemented i18n-js support in WebSync. This came around after realizing my localization support for the JavaScript front end was lacking.

The i18n-js library is super useful and integrates directly with Sprockets and I18n making it as easy as doing:

//= require i18n
//= require i18n/translations

// Some translation
I18n.t('translate-me')

However it’s designed for use with Rails and thus doesn’t play nicely with Sinatra and sinatra-asset-pipeline. While it loaded just fine, Sprockets couldn’t find the i18n javascript files.

Crazy Postgres Queries

Tue, 16 Dec 2014 09:14:00 +0000

I’ve been working on implementing search for documents. I’m not sure if I’m every going to implement search for body content, but I thought I should probably implement it for titles & users.

It turns out that PostgreSQL has pretty nice full text search support with lexemes. I’ve been following this article pretty closely:

http://blog.lostpropertyhq.com/postgres-full-text-search-is-good-enough/

The only issue I’ve encountered is that it doesn’t do direct text matching. For example if you have a title ‘Bananas are tasty!’ and you search for ‘ban’ it won’t match. To work around this I combined full text search with an non case sensitive pattern match. My query is getting kind of long, but it seems to work well.

How about charts in WebSyn.ca?

Sun, 16 Nov 2014 03:36:00 +0000

I did a bunch of work on WebSyn.ca this weekend. Here’s a list of some things I did:

Make charts persistent
Make a nicer interface for inserting them
Adding a bunch of options such as type, titles (main, x, y), legend, smooth lines
Chart Types: Line, Bar, Radar, Polar Area, Pie, Doughnut
Updated require.js
Make tables.js and charts.js use the require.js copy of WebSync.
Shift a huge number of dependencies to load from bower (thus making updating easier).

I’m sure you’re more interested in the picture than the comments.

WebSyn.ca updates! Finally!

Sat, 15 Nov 2014 08:56:56 +0000

I finally got some free time since my midterms are over, and I decided to work on WebSyn.ca. I fixed a couple of bugs such as fixing file export.

I also decided to update the overall visual style and update the format of the file list page. The previous style was pretty terrible and just an HTML table. The newer version is pretty much the same thing but looks a bit more like an actual file manager.

WebSyn.ca migration

Mon, 14 Jul 2014 02:10:58 +0000

WebSyn.ca was down for ten minutes while migrating to a new server. Everything should be working now.

Sketchy URL Shortener Traffic Stats

Thu, 26 Jun 2014 05:09:07 +0000

Here’s some stats from the sketchy URL shortener. I’m really surprised it got so much traffic.

Hey look! I made a landing page!

Wed, 11 Jun 2014 21:54:26 +0000

http://fn.lc

I’m not terribly happy with it. It seems a bit bland and confusing. I’ll probably add some explanatory text to the top.

Content aside, the setup is kind of neat. It uses erb, scss, and vim to render the code into html.

“vim -f -n code.js +TOhtml +wq +q“

It’s interesting that you can use vim to modify/export files programmatically.
I also setup mina for deployment. It makes pushing a new version of the site as easy as running “mina deploy”. Thank the FSM for deployment systems.

WebSyn.ca Equation Support

Wed, 14 May 2014 05:20:43 +0000

I’ve implemented basic =eqn() support in WebSync. Right now it just executes some javascript if the text in the cell starts with =. I’ve also added in one helper function that returns the value of the cell in the format c("A1").

We’ll see how this goes. I’m extremely hesitant to allow people to run untrusted javascript code on people’s browsers. I might have to add in a “This document uses untrusted javascript, are you willing to accept any consequences?” on page load. A lot of the damage the untrusted script might do is mitigated by the backend. WebSync by default refuses all XHR requests except to specific endpoints. This should stop all attempts to damage other documents if they’re using a browser that properly implements XHR headers (which, as far as I know, is all of them).

WebSyn.ca Custom CSS

Sat, 03 May 2014 04:38:43 +0000

I just added easy custom CSS on WebSync documents. It might not be for the best… However, it works quite well and like everything you can edit the css in one window and preview the changes on the other. :D

A future update might add some sort of local CSS so you can only customize things under the .content_well div. Right now you can style anything on the page.

New WebSync styling.

Fri, 18 Apr 2014 05:54:00 +0000

Ok, there ...

Fri, 18 Apr 2014 03:12:21 +0000

Ok, there was a need for OPENSSL_cleanse() instead of bzero() to prevent supposedly smart compilers from optimizing memory cleanups away. Understood.

Ok, in case of an hypothetically super smart compiler, OPENSSL_cleanse() had to be convoluted enough for the compiler not to recognize that this was actually bzero() in disguise. Understood.

But then why there had been optimized assembler versions of OPENSSL_cleanse() is beyond me. Did someone not trust the C obfuscation?

First Post

Tue, 15 Apr 2014 03:22:07 +0000

Hi there!