RMT.rs: High-Performance Registration Path for RMT using Rust by gbasso

Description

The SUSE Repository Mirroring Tool (RMT) is a critical component for managing software updates and subscriptions, especially for our Public Cloud Team (PCT). In a cloud environment, hundreds or even thousands of new SUSE instances (VPS/EC2) can be provisioned simultaneously. Each new instance attempts to register against an RMT server, creating a "thundering herd" scenario.

We have observed that the current RMT server, written in Ruby, faces performance issues under this high-concurrency registration load. This can lead to request overhead, slow registration times, and outright registration failures, delaying the readiness of new cloud instances.

This Hackweek project aims to explore a solution by re-implementing the performance-critical registration path in Rust. The goal is to leverage Rust's high performance, memory safety, and first-class concurrency handling to create an alternative registration endpoint that is fast, reliable, and can gracefully manage massive, simultaneous request spikes.

The new Rust module will be integrated into the existing RMT Ruby application, allowing us to directly compare the performance of both implementations.

Goals

The primary objective is to build and benchmark a high-performance Rust-based alternative for the RMT server registration endpoint.

Key goals for the week:

1. Analyze & Identify: Dive into the SUSE/rmt Ruby codebase to identify and map out the exact critical path for server registration (e.g., controllers, services, database interactions).
2. Develop in Rust: Implement a functionally equivalent version of this registration logic in Rust.
3. Integrate: Explore and implement a method for Ruby/Rust integration to "hot-wire" the new Rust module into the RMT application. This may involve using FFI, or libraries like rb-sys or magnus.
4. Benchmark: Create a benchmarking script (e.g., using k6, ab, or a custom tool) that simulates the high-concurrency registration load from thousands of clients.
5. Compare & Present: Conduct a comparative performance analysis (requests per second, latency, success/error rates, CPU/memory usage) between the original Ruby path and the new Rust path. The deliverable will be this data and a summary of the findings.

Resources

• RMT Source Code (Ruby):
  • https://github.com/SUSE/rmt
• RMT Documentation:
  • https://documentation.suse.com/sles/15-SP7/html/SLES-all/book-rmt.html
• Tooling & Stacks:
  • RMT/Ruby development environment (for running the base RMT)
  • Rust development environment (rustup, cargo)
• Potential Integration Libraries:
  • rb-sys: https://github.com/oxidize-rb/rb-sys
  • Magnus: https://github.com/matsadler/magnus
• Benchmarking Tools:
  • k6 (https://k6.io/)
  • ab (ApacheBench)

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Looking at Rust if it could be an interesting programming language by jsmeix

Get some basic understanding of Rust security related features from a general point of view.

This Hack Week project is not to learn Rust to become a Rust programmer. This might happen later but it is not the goal of this Hack Week project.

The goal of this Hack Week project is to evaluate if Rust could be an interesting programming language.

An interesting programming language must make it easier to write code that is correct and stays correct when over time others maintain and enhance it than the opposite.

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Build a terminal user-interface (TUI) for Agama by IGonzalezSosa

Description

Officially, Agama offers two different user interfaces. On the one hand, we have the web-based interface, which is the one you see when you run the installation media. On the other hand, we have a command-line interface. In both cases, you can use them using a remote system, either using a browser or the agama CLI.

We would expect most of the cases to be covered by this approach. However, if you cannot use the web-based interface and, for some reason, you cannot access the system through the network, your only option is to use the CLI. This interface offers a mechanism to modify Agama's configuration using an editor (vim, by default), but perhaps you might want to have a more user-friendly way.

Goals

The main goal of this project is to built a minimal terminal user-interface for Agama. This interface will allow the user to install the system providing just a few settings (selecting a product, a storage device and a user password). Then it should report the installation progress.

Resources

• https://agama-project.github.io/
• https://ratatui.rs/

Conclusions

We have summarized our conclusions in a pull request. It includes screenshots ;-) We did not implement all the features we wanted, but we learn a lot during the process. We know that, if needed, we could write a TUI for Agama and we have an idea about how to build it. Good enough.

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Learn a bit of embedded programming with Rust in a micro:bit v2 by aplanas

Description

micro:bit is a small single board computer with a ARM Cortex-M4 with the FPU extension, with a very constrain amount of memory and a bunch of sensors and leds.

The board is very well documented, with schematics and code for all the features available, so is an excellent platform for learning embedded programming.

Rust is a system programming language that can generate ARM code, and has crates (libraries) to access the micro:bit hardware. There is plenty documentation about how to make small programs that will run in the micro:bit.

Goals

Start learning about embedded programming in Rust, and maybe make some code to the small KS4036F Robot car from keyestudio.

Resources

• micro:bit
• KS4036F
• microbit technical documentation
• schematic
• impl Rust for micro:bit
• Rust Embedded MB2 Discovery Book
• nRF-HAL
• nRF Microbit-v2 BSP (blocking)
• knurling-rs
• C++ microbit codal
• microbit-bsp for Embassy
• Embassy

Diary

Day 1

• Start reading https://mb2.implrust.com/abstraction-layers.html
• Prepare the dev environment (cross compiler, probe-rs)
• Flash first code in the board (blinky led)
• Checking differences between BSP and HAL
• Compile and install a more complex example, with stack protection
• Reading about the simplicity of xtask, as alias for workspace execution
• Reading the CPP code of the official micro:bit libraries. They have a font!

Day 2

• There are multiple BSP for the microbit. One is using async code for non-blocking operations
• Download and study a bit the API for microbit-v2, the nRF official crate
• Take a look of the KS4036F programming, seems that the communication is multiplexed via I2C
• The motor speed can be selected via PWM (pulse with modulation): power it longer (high frequency), and it will increase the speed
• Scrolling some text
• Debug by printing! defmt is a crate that can be used with probe-rs to emit logs
• Start reading input from the board: buttons
• The logo can be touched and detected as a floating point value

Day 3

• A bit confused how to read the float value from a pin

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Arcticwolf - A rust based user space NFS server by vcheng

Description

Rust has similar performance to C. Also, have a better async IO module and high integration with io_uring. This project aims to develop a user-space NFS server based on Rust.

Goals

• Get an understanding of how cargo works
• Get an understanding of how XDR was generated with xdrgen
• Create the RUST-based NFS server that supports basic operations like mount/readdir/read/write

Result (2025 Hackweek)

• In progress PR: https://github.com/Vicente-Cheng/arcticwolf/pull/1

Resources

https://github.com/Vicente-Cheng/arcticwolf

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early stage kdump support by mbrugger

Project Description

When we experience a early boot crash, we are not able to analyze the kernel dump, as user-space wasn't able to load the crash system. The idea is to make the crash system compiled into the host kernel (think of initramfs) so that we can create a kernel dump really early in the boot process.

Goal for the Hackweeks

1. Investigate if this is possible and the implications it would have (done in HW21)
2. Hack up a PoC (done in HW22 and HW23)
3. Prepare RFC series (giving it's only one week, we are entering wishful thinking territory here).

update HW23

• I was able to include the crash kernel into the kernel Image.
• I'll need to find a way to load that from init/main.c:start_kernel() probably after kcsan_init()
• I workaround for a smoke test was to hack kexec_file_load() systemcall which has two problems:
  1. My initramfs in the porduction kernel does not have a new enough kexec version, that's not a blocker but where the week ended
  2. As the crash kernel is part of init.data it will be already stale once I can call kexec_file_load() from user-space.

The solution is probably to rewrite the POC so that the invocation can be done from init.text (that's my theory) but I'm not sure if I can reuse the kexec infrastructure in the kernel from there, which I rely on heavily.

update HW24

• Day1
  • rebased on v6.12 with no problems others then me breaking the config
  • setting up a new compilation and qemu/virtme env
  • getting desperate as nothing works that used to work
• Day 2
  • getting to call the invocation of loading the early kernel from __init after kcsan_init()

• Day 3

  • fix problem of memdup not being able to alloc so much memory... use 64K page sizes for now
  • code refactoring
  • I'm now able to load the crash kernel
  • When using virtme I can boot into the crash kernel, also it doesn't boot completely (major milestone!), crash in elfcorehdr_read_notes()

• Day 4

  • crash systems crashes (no pun intended) in copy_old_mempage() link; will need to understand elfcorehdr...
  • call path vmcore_init() -> parse_crash_elf_headers() -> elfcorehdr_read() -> read_from_oldmem() -> copy_oldmem_page() -> copy_to_iter()

• Day 5

  • hacking arch/arm64/kernel/crash_dump.c:copy_old_mempage() to see if crash system really starts. It does.
  • fun fact: retested with more reserved memory and with UEFI FW, host kernel crashes in init but directly starts the crash kernel, so it works (somehow) \o/

update HW25

• Day 1
  • rebased crash-kernel on v6.12.59 (for now), still crashing

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Improve UML page fault handler by ptesarik

Description

Improve UML handling of segmentation faults in kernel mode. Although such page faults are generally caused by a kernel bug, it is annoying if they cause an infinite loop, or panic the kernel. More importantly, a robust implementation allows to write KUnit tests for various guard pages, preventing potential kernel self-protection regressions.

Goals

Convert the UML page fault handler to use oops_* helpers, go through a few review rounds and finally get my patch series merged in 6.14.

Resources

Wrong initial attempt: https://lore.kernel.org/lkml/20231215121431.680-1-petrtesarik@huaweicloud.com/T/

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Add Qualcomm Snapdragon 765G (SM7250) basic device tree to mainline linux kernel by pvorel

Qualcomm Snapdragon 765G (SM7250) (smartphone SoC) has no support in the linux kernel, nor in u-boot. Try to add basic device tree support. The hardest part will be to create boot.img which will be accepted by phone.

UART is available for smartphone :).

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dynticks-testing: analyse perf / trace-cmd output and aggregate data by m.crivellari

Description

dynticks-testing is a project started years ago by Frederic Weisbecker. One of the feature is to check the actual configuration (isolcpus, irqaffinity etc etc) and give feedback on it.

An important goal of this tool is to parse the output of trace-cmd / perf and provide more readable data, showing the duration of every events grouped by PID (showing also the CPU number, if the tasks has been migrated etc).

An example of data captured on my laptop (incomplete!!):

          -0     [005] dN.2. 20310.270699: sched_wakeup:         WaylandProxy:46380 [120] CPU:005
          -0     [005] d..2. 20310.270702: sched_switch:         swapper/5:0 [120] R ==> WaylandProxy:46380 [120]
...
    WaylandProxy-46380 [004] d..2. 20310.295397: sched_switch:         WaylandProxy:46380 [120] S ==> swapper/4:0 [120]
          -0     [006] d..2. 20310.295397: sched_switch:         swapper/6:0 [120] R ==> firefox:46373 [120]
         firefox-46373 [006] d..2. 20310.295408: sched_switch:         firefox:46373 [120] S ==> swapper/6:0 [120]
          -0     [004] dN.2. 20310.295466: sched_wakeup:         WaylandProxy:46380 [120] CPU:004

Output of noise_parse.py:

Task: WaylandProxy Pid: 46380 cpus: {4, 5} (Migrated!!!)
        Wakeup Latency                                Nr:        24     Duration:          89
        Sched switch: kworker/12:2                    Nr:         1     Duration:           6

My first contribution is around Nov. 2024!

Goals

• add more features (eg cpuset)
• test / bugfix

Resources

• Frederic's public repository: https://git.kernel.org/pub/scm/linux/kernel/git/frederic/dynticks-testing.git/
• https://docs.kernel.org/timers/no_hz.html#testing

Progresses

isolcpus and cpusets implemented and merged in master: dynticks-testing.git commit

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Backporting patches using LLM by jankara

Description

Backporting Linux kernel fixes (either for CVE issues or as part of general git-fixes workflow) is boring and mostly mechanical work (dealing with changes in context, renamed variables, new helper functions etc.). The idea of this project is to explore usage of LLM for backporting Linux kernel commits to SUSE kernels using LLM.

Goals

• Create safe environment allowing LLM to run and backport patches without exposing the whole filesystem to it (for privacy and security reasons).
• Write prompt that will guide LLM through the backporting process. Fine tune it based on experimental results.
• Explore success rate of LLMs when backporting various patches.

Resources

• Docker
• Gemini CLI

Repository

Current version of the container with some instructions for use are at: https://gitlab.suse.de/jankara/gemini-cli-backporter

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