Building a JavaScript Optimization Engine (Joe) | Probably writing code | often qti3e | π¦π³οΈβπ
San Francisco, CA
Joined November 2022
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Parsa retweeted
Everyone's trying to make CPUs faster.
Iβm trying to make them worse.
New project: CPU deoptimization.
Searching for the slowest possible machine instructions
x86 single instruction record:
198,002,498,236 cycles, 62 seconds
The assembly hall of shame: github.com/xoreaxeaxeax/asm-β¦
Parsa retweeted
Pentium 4 propaganda!
Branch predictor hints (the 0x2e/3e prefix) on most modern CPUs don't have any effect, the important thing is about putting the likely paths near and making the unlikely case a far jump.
This improves the performance by putting less pressure on the frontend and icache for instruction that you're likely to not run.
C's original design, and to great extent still true to this day, is a line-by-line compiled language so to create that same effect what you do is you put the unlikely cases at the end of the function and use "goto" statements.
So C actually had the most manual branch hint tooling (goto), later compilers and languages gave likely/unlikely/#[cold] so they could do that same basic block linearization for you instead forcing you to write the code in its assembly instruction order.
And there is always inline asm xD
Parsa retweeted
I left K3 running autonomously for 3 days with a goal to get OpenBSD working on my reMarkable Paper Pro. It reverse engineered the boot flow by doing lots of HW experiments and got the kernel booting just now!
Parsa retweeted
as someone who literally reverse engineered the XZ attack, this is how you get more XZ attacks.
suuure letβs just bundle already compiled blobs into other compiled blobs. itβs real fun to audit compressed garbage.
Parsa retweeted
completely false. the real programmer's model is the actual microarchitecture.
As a programmer, if you think about the CPU as circuits and electricity.... You might be getting it all wrong.
As a programmer this is what you need to know about the CPU is - the programmer's model.
It is an abstraction that lets you visualise the CPU as a state-machine having certain essential elements to it, primarily to read instructions and manipulate data.
Once you have a clear idea of what it is, you will be able to reason clearly about the programs, their performance and the limitations.
I ported over yet another chapter from my book to the web, here's the link - code.pyjamacafe.com/courses/β¦
Parsa retweeted
Iβm convinced that a large % of programmers donβt actually like computers.
As a side effect, are also perfectly happy to throw away their reasoning to a model as soon as they can.
I donβt get it, at ALL. Donβt you *LIKE* understanding the magic of the machine?
You do realize hand-programming (I hate that I even have to specify hand now) is funβ¦right?
Parsa retweeted
ADHD isn't a disorder.
It's a nervous system designed for a world that DOES NOT EXIST anymore.
Let me explain:
Parsa retweeted
Introducing Willow, our new state-of-the-art quantum computing chip with a breakthrough that can reduce errors exponentially as we scale up using more qubits, cracking a 30-year challenge in the field. In benchmark tests, Willow solved a standard computation in <5 mins that would take a leading supercomputer over 10^25 years, far beyond the age of the universe(!).
Parsa retweeted
Docker is stupid.
βSorry, we canβt deploy a single statically linked executable of size 10 MB, so
LETβS JUST SHIP GIGABYTES OF DATA CONTAINING AN ENTIRE OS WITH ALL DEPENDENCIES FOR EVERY SINGLE SERVICEβ
Parsa retweeted
If you didn't notice this week, we did a lil' UI revamp β‘
We've introduced a new vertical sidebar navigation and enhanced our breadcrumb accessibility, making navigation throughout the app easier.
This is just the beginningβmore improvements are on the way π
Parsa retweeted
Next.js be like
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