gajjanag

Joined 11 years ago

Karma
433
Submissions
192
Member since
Jul 25
Software engineer with a keen interest in high performance computing. In the past, PhD from MIT in EECS in a mix of applied mathematics and computer science.

Research interests: a broad range of applied mathematics topics, generally in the neighborhood of information theory and probability.

Other interests: mathematics in general, computer systems (especially security), FOSS projects, reading, bicycling, and cooking.

Website: gajjanag.github.io

[ my public key: https://keybase.io/gajjanag; my proof: https://keybase.io/gajjanag/sigs/-vv1qyl9QGR_46BS-LPAm3wBVPYna8zjMyUzDBWVKWg ]

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Recent submissions

Comment · 1 month ago
> The entire essay is about stopping development until it can be made more safe, with specific ideas on how to do that.

No, the essay does not talk about "stopping development". That's a very clever sleight of hand made in the essay to get readers to draw this false conclusion.

It just talks about building AI at a "balanced rate". Untangling the corporate speak, this amounts to essentially "go full steam ahead, but have more eval oversight before release".

Comment · 1 month ago
Comment · 2 months ago
> You will typically find your staff and higher level engineers rarely are actually writing code themselves.

Many so called staff+ engineers are basically glorified Google Docs engineers, or management who want to call themselves technical. It seems to be fashionable these days to call oneself "technical" without actually knowing anything of the problem domain.

They basically take all the "credit" for any innovation out of the team, and scapegoat other teams when project deliverables are not met.

Comment · 5 months ago
> Communication matters most when you're dealing with cross-org concerns and those that master it are usually the more friendly and pleasant ones.

I don't agree with the second one, but agree with the first.

Throughout my corporate career so far, I have found plenty of hot air/pretty picture slide decks that exist solely for ladder climbers to climb. Said ladder climbers are usually all smiles in public and "friendly", but you have to watch out for knives behind your back.

Comment · 6 months ago
> Thanks for that! It is worth noting that taking advantage of the post-rotation distribution

I again feel this claim is too strong. Rotations have been used in information theory/wireless communications for decades at this point, with appropriate scaling done at channel inputs/outputs to hit channel capacity. The signals then pass through the appropriate codebooks that take advantage of the post-rotated+whitened signal.

Our cellphones today are powered by such technology.

I agree with your claim when restricted to deep learning. But I do not agree with the broad characterization that taking advantage of post-rotation distributions was only first done in your work.

Comment · 6 months ago
Wow, yes - you are completely correct (read through the note in detail now).

Though, as your paper also notes, the quantizer values themselves aren't fundamentally novel to either paper. Lloyd Max scalar quantizers have been studied for a very, very long time. And the specific Lloyd Max values for the Gaussian input distribution have been obtained in many papers across signal processing and information theory.

Comment · 6 months ago
Comment · 6 months ago
TurboQuant is known across the industry to not be state of the art. There are superior schemes for KV quant at every bitrate. Eg, SpectralQuant: https://github.com/Dynamis-Labs/spectralquant among many, many papers.

> Given that TurboQuant results in a 6x reduction in memory usage for KV caches

All depends on baseline. The "6x" is by stylistic comparison to a BF16 KV cache; not a state of the art 8 or 4 bit KV cache scheme.

Comment · 6 months ago
Comment · 8 months ago
> That's why you need to put your scope

The problem is, "scope" is often equated to "how many people worked in my empire" rather than "how much business value did my work X generate".

The two things are vastly different, and I have seen the distinction/oversimplification play out over and over in my own career as well as many others around me.

As an extreme on the "individual technical expert side", there are things out there that can pretty much only be accomplished with a few people around the world who possess the dedicated expertise. These results can't be replicated by a cobbled together team of 10 or 100 people even though the latter sounds more impressive for "scope".

Some organizations do a decent job of recognizing these different "archetypes", many don't.

Comment · 1 year ago
>80%-90% or so of real life vectorization can be achieved in C or C++ just by writing code in a way that it can be autovectorized.

Yep. I was pleasantly surprised by the autovectorization quality with recent clang at work a few days ago. If you write code that the compiler can infer to be multiples of 4, 8, etc the compiler goes off and emits pretty decent NEON/AVX code. The rest as you say is handled quite well by intrinsics these days.

Autovectorization was definitely poorer 5-10 years ago on older compiler toolchains.

Comment · 1 year ago
Welcome to the brave new world these days:

1 - Very few people conduct "proper scholarship", and fail to trace ideas back to their original inception and cite them correctly. This happens time and again in deep learning, where 30+ year old ideas are claimed as "novel" over and over. Many times out of malice by the authors, sometimes out of ignorance.

2 - Peer review in many parts of the industry+research is a joke. Mostly shouldered by early graduate students who don't really know the field well and an incredibly noisy process.

3 - It is common practice now to dump out one's "kitchen sink" of ideas rather than properly refined stuff. Hence the increase in LinkedIn spam, blog spam, arXiv spam style of papers.

Comment · 1 year ago
> I don't think there are many (or any) upsides to the well documented downsides.

C++ template metaprogramming still remains extremely powerful. Projects like CUTLASS, etc could not be written to give best performance in as ergonomic a way in Rust.

There is a reason why the ML infra community mostly goes with Python-like DSL's, or template metaprogramming frameworks.

Last I checked there are no alternatives at scale for this.

Comment · 1 year ago
As others have pointed out, these phenomena are well known to many folks across companies in the AI infra space. It doesn't really break new ground. This article is a good exposition of the basic strategies though.

What I would have loved is a discussion around collectives/multi-node setups. And showing how to get determinism at low performance penalty for multi-node reduction collectives.

Comment · 1 year ago
I guess you have never worked with a slow induction cooktop. Literally we had to spend 15 minutes more for cooking things on induction compared with our previous apartment's gas connection.

Maybe they are better now but it is certainly not the case that all induction cooktops have these magical properties; many are cheap and skimp on something. While in the 5+ apartments I have been in gas has always delivered the same heating experience that I can rely on.

And to your point about rotis, no - it can not be done unless you get a different, heavier bottomed pan suitable for induction. Exactly what I was saying regarding the replacement costs.

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