mshockwave

1,083 karma · joined September 22, 2015

Interested in Compilers, Code Generation, Static Analysis, System Software and System Security. Familiar with LLVM.

meet.hn/city/33.6856969,-117.8259810/Irvine

mshockwaveon Static Basic Block Versioning

I'm actually glad to see that restriction in their study, because there are many cases where you just can't / more difficult to use PGO. One of the most common reasons I ran into is that clients refuse to use it (no, I'm not even joking), either they don't know how to come up with a good training data (in which case they'll point at your nose shouting IT DOESN'T WORK!!) or they thought it's a stupid idea (again, not joking). You'll be amazed by some people's stubbornness

mshockwaveon Ring-Based Mid-Air Gesture Typing System Using Deep Learning Word Prediction

I only buy keyboards, even when I wanted a compact one, with home/end keys because it's so much more productive especially in coding in a terminal.

mshockwaveon Optimizers need a rethink

> If you’re relying on it then you’re playing with fire.

Unfortunately I think Linux kernel is one of the most notable examples in which case you have to compile with -O1 or up.

mshockwaveon NASA freezes Starliner missions

NASA used to be nice over SLS was that they really didn't have a choice + congress pressure (hiring people who lost their jobs due to space shuttle cancelation) but now it seems like NASA _does_ have a choice to choose an alternative (and waaay cheaper) vehicle over SLS. Curious whether those senators will keep their pressure.

mshockwaveon A not so fast implementation of cosine similarity in C++ and SIMD

can confirm fast math makes the biggest difference

mshockwaveon A not so fast implementation of cosine similarity in C++ and SIMD

which flags did you use and which compiler version?

mshockwaveon Starship Flight 5: Launch and booster catch [video]

I have the same feeling watching Starship when the telemetry on the bottom right of the screen showing “0km” but landing burn hasn’t started. Later did I know that it was meant to start the burn only a few hundreds _meters_ from the ground

mshockwaveon Starship Flight 5: Launch and booster catch [video]

I think saving weight is definitely one of the main issues, see those proportionally large legs on Falcon-9, I guess it simply doesn't scale on bigger vehicles like Starship / Heavy booster. Also, by catching the booster on site, they can even save the transportation and do the refurbishing on site, so even shorter turnaround time I guess.

mshockwaveon WASM Is the New CGI

> Heh, there were literally CPUs with some support for the JVM!

Jazelle, a dark history that ARM never wants to mention again

mshockwaveon MikroPhone: A privacy enhanced, simple and featured RISC-V mobile phone

I was just wrapping my head around on how do they even run linux on the RISC-V microcontroller they use. Turns out there is a separate ARM for application processor.

mshockwaveon UK launches its first Earth-imaging military satellite

Because it’s probably not the real number. The reason why they wanted to release at least _some_ specs is probably because congress / parliament

mshockwaveon AMD's Strix Point: Zen 5 Hits Mobile

Switching from individual schedulers to unified one for integer execution makes sense to me, but I still don’t quite understand why FP execution units do the opposite, could somebody explain why?

mshockwaveon The Linux Kernel Module Programming Guide

LLM likes to use "delve" doesn't mean every usages of "delve" imply LLM

mshockwaveon Misconceptions about loops in C

LLVM tries to canonicalize all the loops into one of the two canonical forms[1] before doing any useful analysis and transformations. It has been quite effectives. Not all loops can be shaped into a canonical one though.

[1]: https://llvm.org/docs/LoopTerminology.html

mshockwaveon NASA indefinitely delays return of Starliner to review propulsion data

I'm not an expert in this field but I feel like the key is to make Dragon as a platform cheap, and once that happens more rides can be carried (to ISS) hence making the system battle-tested. Being cheap and reliable are the two major reasons NASA rode with Soyouz in the past few decades and, for better or for worse, still riding with them even after the Ukraine war started.

mshockwaveon NASA indefinitely delays return of Starliner to review propulsion data

could somebody ELI5 what is happening to this program? delays after delays, and now they might need to send another spacecraft to bring people back. It will be hilarious if that turns out to be a SpaceX Dragon.

mshockwaveon The Qualcomm Snapdragon X Architecture Deep Dive: Getting to Know Oryon

I feel like Microsoft's current stand on this is weird. They're either not as enthusiasting as Qualcomm and just riding along, or their terrible execution makes them move really slow.

mshockwaveon Swift Static Linux SDK

> Not sure I understand that. Is it something specific to Swift, or is it exactly what is expected from using shared libraries?

More of a shared library issue I believe.

> Say my Linux distribution distributes some Swift runtime, then the corresponding Swift packages should have been built for this runtime as well. Just like when my Linux distribution distributes a libc, the corresponding packages need to be built for this libc. Right?

That's correct

mshockwaveon Finding out where syscalls are called from: Stack traces with strace

Today I definitely learned! I feel like we can just patch strace to read debug info (and use it in stack trace) when present.

mshockwaveon Explosively pumped flux compression generator

And IIUC this is used to generate EMP without using nuke, so you’ll knock out the whole neighborhood powergrid too!

mshockwaveon Love to see the night sky on Mars? This is what it would be like to stargaze

Maybe ones similar to the patterns on our moon made by craters

mshockwaveon Show HN: ADS-B visualizer

I'm surprised about this, I thought it's pretty easy to add ADS-B to modern IFF module and they can just switch between different modes.

mshockwaveon Skin in the Game

I also have a similar feeling. Though I think OP is talking about open source contributions which might be different from more casual forums and IRC.

mshockwaveon Documentation for the AMD 7900XTX

With my past experience in Khronos, NVIDIA is indeed a member and they sent decent guys to the meetings -- but only for strategic reasons, rather than "advocating for open standards" as you described. My experiences there actually told me the opposite that they will never drop CUDA. Objectively they also have incentive to do so: fighting with 100-ish companies to ratify something is always slower than rolling out an feature in an ecosystem you have total control of.

mshockwaveon Sequential and parallel execution of long-running shell commands

A similar tool I highly recommend: https://github.com/justanhduc/task-spooler

At first I thought it would just be a one-off tool I used for one of my projects, not until I discovered later that it has everything I need and became my daily driver ever since.

mshockwaveon Hurried Thoughts: You're Wrong About Tidal-Locking

I thought that’s what happens on Pluto

mshockwaveon A supply chain attack on PyTorch

compare to Boeing's volume? maybe, but Airbus is one of _Europe_'s largest defense contractors

mshockwaveon How we turned the tide in the roach wars

I know many tropical countries have successful stories fighting mosquitos by simply removing every single place that might contain water: ponds, flower pots etc.

mshockwaveon The risk of RISC-V: What's going on at SiFive?

Motorola 68k has this kind of aligned variable length instructions (in their case it’s always aligned on 16 bit boundaries). It’s not super difficult to support this in compilers though

mshockwaveon Extreme parkour with legged robots

not sure what you trying to get, but hundreds if not thousands of universities are working closely with DARPA, which is an DoD agency that sponsors mostly high-level and non-classified researches. Many of the researches have weak connections to actual military usages (there has to be _some_ connections, but many of them are pretty weak).