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Voloskaya

Re:Indefinite Backpack Travel on Tuesday October 07, 2025 @08:06AM (#45502109)
Fair, didn’t mean to strawman.
Re:Indefinite Backpack Travel on Monday October 06, 2025 @02:36PM (#45494661)
> Odds are that shirt had already sailed around the world once or twice by the time you buy it,

That's like... 40 grams of CO2 for those 2 trips for a t-shirt. Aka, a 2 min uber ride.

Shipping containers are incredibly efficient.

Modern large container ships consume about 200-300 tonnes of fuel per day, and could carry 742 millions t-shirts [1]. It takes 16 days to do something like Shanghai - LA, so that ends up being like 20 grams per shirt per trip.

[1]: https://www.howandwhy.com/15-mins/huge-ship-shirts

Your argument boils down to "people already said some things like this in the past" (ok, and?) and "some people I don't like agree with part of it", which is very weak and doesn't address anything in substance.

You know, you can still want to be able to build housing without having to wait 1 year for permitting or not want to live in a place where making a basic train track is basically impossible because of the number of stakeholders that have to come to a consensus and still vote for Mamdani. You are allowed to have non black and white opinions.

You can even have 1% of the things you think are good in common with Peter Thiel, and that won't immediately turn you into a far right psychopath.

You can even, hear me out, be for less regulation on specific areas where there has been a massive lack of supply but not for "deregulating the economy" in it's entirety!

This is basically the entire theme of "Abundance" by Klein and Thompson, for those looking for a longer read on this.

[1]: https://en.wikipedia.org/wiki/Abundance_(Klein_and_Thompson_...

> they set their hiring bar for engineers too high

Not sure I agree, if you look at the head count growth of companies like OpenAI, Anthropic etc, it is super fast, its already pretty hard to keep everything working smoothly with that rate of employee growth, so going faster than that seems very risky.

Ultimately I think it's mostly caused by the field still being so new. Everything still needs to be optimized and there just aren't that many very good CUDA programmers to start with, then you need to find one that also has deep knowledge of ML and transformers architectures, which further drains the pool. And then when you do find one of them, there is 50 different things they could be working on instead of what's in the article, all equally or more impactful. The architectures being constantly evolving also make it hard/not a great ROI to go super super deep in single digit % optimization when there is new stuff coming out all the time that can be made an order of magnitude faster.

A good example of that is flash attention: it is maybe the most significant/impactful optimization in ML of the last few years. Tl;dr is how do you fuse the entire attention pipeline together to make it much faster and avoid massive tensor materialization. The bottleneck was obvious to anyone that profiled a Transformer-based model, but there was no obvious solution because of how softmax works. Yet the paper that ultimately unblock this was published back in 2019 [1], but it took 3 years for a team to connect the dots. Most people in pure ML engineering didn't know about the paper and don't have good enough CUDA knowledge/ GPU arch understanding, most people with good CUDA knowledge don't understand ML well enough, and even the author of that 2019 paper said "[we] hypothesize that this reduction in memory accesses should improve Softmax performance on actual hardware" but didn't have the technical skills to test this or to see how that could be part of a bigger breakthrough because it requires understanding core concepts in how GPU worked and compute/memory imbalance.

[1]: https://arxiv.org/pdf/1805.02867

> I can only assume all these ideas have been widely implemented at all significant labs for years, right?

Nope.

I was also surprised, when joining such significant labs at how much relatively-low hanging fruits were still available to work on. But the reality is that there is just too much work to do, each seemingly super-important, and not enough people to do it.

Re:Cerebras Systems Raises $1.1B Series G at $8.1B Valuation on Wednesday October 01, 2025 @11:42AM (#45439085)
> What about for inference?

Same techniques apply.

> but did not dispute that they store the entire model on SRAM.

No idea what they did or did not do for that specific test (which was about delivering 1800 tokens/sec though, not simply running qwen-3) since they didn't provide any detail. I don't think there is any point storing everything in SRAM, even if you do happen to have 100M$ worth of chips lying around in a test cluster at the office, since WSE-3 is designed from the ground up for data parallelism (see [1] section 3.2) and inference is sequential both within a single token generation (you need to go through layer 1 before you can go through layer 2 etc.) and between tokens (autoregressive, so token 1 before token 2). This means most of your weights loaded in SRAM would be just sitting unused most of the time, and when they need to be used they need to be broadcasted to all chips from the SRAM of the chip that has the particular layer you care about, this is extremely fast, but external memory is certainly fast enough to do this if you fetch the layer in advance. So the way to get the best ROI on such a system would be to pack the biggest batch size you can (so many users' queries) and process them all in parallel, streaming the weights as needed. The more your SRAM is occupied by batch activations and not parameters, the better the compute density and thus $/flops.

You can check the Cerebras doc to see how weight streaming works [2]. From the start, one of the selling point of Cerebras is the possibility to scale memory independently of compute, and they have developped an entire system specifically for weight streaming from that decoupled memory. Their docs seems to keep things fairly simple assuming you can only fit one layer in SRAM and thus they fetch things sequentially, but if you can store at least 2 layers in those 44GB of SRAM then you can simply fetch l+1 when l is starting to compute, completely masking latency cost. Its possible they already mask the latency even within a single layer by streaming by tiles for matmul though, unclear from their docs. They mention that in passing in [3] section 6.3.

All of their doc is for training since it seems for inference play they have pivoted to selling API access rather than chips, but inference is really the same thing, just without the backprop (especially in their case were they aren't doing pipeline parallelism where you could claim doing fwd+back prop gives you better compute density). At the end of the day whether you are doing training or inference, all you care about is that your cores have the data they need in their registers at the moment they are free to compute, so streaming to SRAM works the same way in both cases.

Ultimately I can't tell you how much it cost to run Qwen-3, you can certainly do it on a single chip + weight streaming, but their specs are just too light on the exact FLOPs and bandwidth to know what the memory movement cost would be in this case (if any), and we don't even know the price of single chip (everyone is saying 3M$ though, regardless of that comment on the other thread). But I can tell you that your math of doing `model_size/sram_per_chip * chip_cost` just isn't the right way to think about this.

[1]: https://arxiv.org/html/2503.11698v1#S3.

[2]: https://training-api.cerebras.ai/en/2.1.0/wsc/cerebras-basic....

[3]: https://8968533.fs1.hubspotusercontent-na2.net/hubfs/8968533...

Re:Sora 2 on Wednesday October 01, 2025 @09:41AM (#45437640)
Well certainly if you don’t want us to discuss the possible implications ahead, then yes we can only close our eyes and learn from hardship once it’s there, but then what do we learn ? To not close our eyes next time ? We could just do that like now.
Re:Cerebras Systems Raises $1.1B Series G at $8.1B Valuation on Wednesday October 01, 2025 @09:39AM (#45437614)
The blog is about training but the technique applies equally well to inference, just like FSDP and kv cache sharing are routinely done in inference on GPUs.

There is just no need to have parameters or kv cache for layer 48 in SRAM when you are currently computing layer 3, you have all the time in the world to move that to SRAM when you get to layer 45 or whatever the maths work out to be for your specific model.

Re:Cerebras Systems Raises $1.1B Series G at $8.1B Valuation on Tuesday September 30, 2025 @07:21PM (#45432501)
This is highly dependent on exact model size, architecture and hardware configurations. If the compute time for some unit of work is larger than the time it takes to transfer the next batch of Params you are good to go. If you are doing it sequentially though then yes you will pay a heavy price, but the idea is to fetch a future layer not the one you need right away.

As a similar example I have trained video models on ~1000 H100 where the vast majority of parameters are sharded and so need to be first fetched on the network before being available on HBM, which is similar imbalance to the HBM vs SRAM story. We were able to fully mask comms time such that not sharding (if it was even possible) would offer no performance advantage.

Re:Cerebras Systems Raises $1.1B Series G at $8.1B Valuation on Tuesday September 30, 2025 @05:56PM (#45431740)
I’m not saying it’s particularly competitive, I’m saying claiming it cost 100M$ to run Qwen is complete lunacy. There is a gulf between those 2 things.

And beyond pure performance competitiveness there are many things that make it hard for Cerebras and to be actually competitive: can they ship enough chips to meet the need of large clusters ? What about the software stack and lack of great support compared to nvidia? Lack of ml engineers that know how to use them, when everyone knows how to use CUDA and there are many things developed on top of it by the community (e.g triton).

Just look at the valuation difference between AMD and Nvidia, when AMD is already very competitive. But being 99% of the way there is still not enough for customers that are going to pay 5B$ for their clusters.

Re:Cerebras Systems Raises $1.1B Series G at $8.1B Valuation on Tuesday September 30, 2025 @05:27PM (#45431460)
> I estimated that they needed over $100m of chips just to do Qwen 3 at max context size

I will point out (again :)), that this math is completely wrong. There is no need (nor performance gains) to store the entire weights of the model in SRAM. You simply store n transformer blocks on-chip and then stream block l+n from external memory to on-chip when you start computing block l, this completely masks the communication time behind the compute time, and specifically does not require you to buy 100M$ worth of SRAM. This is standard stuff that is done routinely in many scenarios, e.g. FSDP.

https://www.cerebras.ai/blog/cerebras-software-release-2.0-5...

Re:Sora 2 on Tuesday September 30, 2025 @03:42PM (#45430286)
Yes the tech is amazing. But tech is not everything, after 20 years of social media, its pretty clear to everyone that those things can have large long term impact both positive and negative for society, discussing the potential impacts of the tech is not being "political", its just being interested in the future.
> But the line between "just cutting a few corners" and prosecutable criminality isn't nearly as bright as we in the peanut gallery like to think

The line maybe isn't bright, but faking data to a potential buyer to make it appear like you have 15x your actual number of users is clearly way past the line you cannot see.

That would be like saying it's hard to know if noon is during the day or night because the exact moment that qualify as "dawn" is hard to discern.

Re:Electronic Arts Goes Private for $52.5B in Largest LBO on Monday September 29, 2025 @11:06AM (#45414754)
Blizzard is part of Activision (now Microsoft), not EA.
It got coverage back then because at the same time as the Amazon was experiencing record fires the administration also allowed record cuts. You can probably see why that doesn’t go well together.

The current administration has reduced deforestation rates in Brazil by around half.

Re:Baldur's Gate 3 Steam Deck – Native Version on Wednesday September 24, 2025 @11:22AM (#45361648)
To be fair, there is world between "extremely high minimum requirements" and a 6 years old laptop, considering laptop of even the current year are never considered super high end rigs.
Re:The death rays that guard life on Monday September 22, 2025 @03:34PM (#45338389)
Absolutely not, most UV is blocked by the ozone layer, this is why we don't all develop skin cancer at 15. Otherwise, what would be the point of the UV-sterilization method?
Re:The death rays that guard life on Monday September 22, 2025 @11:02AM (#45334456)
I would be surprised if there is no dire second order consequences to raising kids 8h per days in a sterile environment (or more if you also adopt this setup at home). The immune system needs to be used in order to work properly. Unless we want a life where we cannot step outside of the range of our UV lamps.
No, it's for new H1-Bs and renewals, and it starts tomorrow.
Re:A postmortem of three recent issues on Wednesday September 17, 2025 @06:03PM (#45281929)
LLMs are still executed by code written by humans. In this case, the model ultimately give you a probability distribution over each (~200k) tokens in the vocabulary. It's then up to you to decide how you want to sample the next token, you could for example just always sample the most likely, or to make the output more creative, you can sample randomly from the top-k tokens. This top-k sampling, to make it efficient, is written in XLA and compiled to run directly as a kernel, there was a bug in that kernel, which presumably led to tokens outside of the top-k window be select from times to times.
They are typically bigger at Nazare, but it all depends on the swell. Its not impossible for Mavericks to receive a swell that could create waves bigger than whatever Nazare has received in the last 20 years, but it's less likely.

However Mavericks is definitely the "nicer" and gnarlier wave of the two imho, Nazare is massive but has no shape, so they just surf the shoulder for 5 seconds and kick out. Mavericks has much nicer lines.

Re:Many Hard LeetCode Problems Are Easy Constraint Problems on Monday September 15, 2025 @01:26PM (#45252478)
Interesting, maybe they stopped doing this then. It used to be that you received a link for an automated online test, with 4 progressively harder questions, and you needed to score 1000/1000 to go the next step and speak to a human.
Re:Many Hard LeetCode Problems Are Easy Constraint Problems on Saturday September 13, 2025 @11:22AM (#45232822)
Might depend on the specific position you applied to. Was it a pure SDE role or more on the research side ?
Re:Vector database that can index 1B vectors in 48M on Friday September 12, 2025 @05:47PM (#45227152)
I assume by "node" OP meant something like a DGX node. Which yea, that would work, but not everyone (no one?) wants to buy a 500k system to do vector search.

B200 spec:

* 8TB/sec HBM bandwidth

* 10 PetaOPs assuming int8.

* 186GB of VRAM.

If we work with 512-dimensional int8 embeddings, then we need 512GB VRAM to hold them, so assuming we have 8xB200 node (~500k$++), we can easily hold them (125M vectors per GPU).

It takes about 1000 OPs to do the dot product between two vectors, so we need to do 1000*1B = 1TeraOPs, spread over 8 GPUs, that's 125 GigaOPs per GPU, so a fraction of a ms.

Now the bottleneck will be data movement between HBM -> chips, since we have 125M vectors per GPU, aka 64GB, we can move them in ~8 ms.

Here you go, the most expensive vector search in history, giving you the same performance as a regular CPU-based vectorDB for only 1000x the price.

Re:Many Hard LeetCode Problems Are Easy Constraint Problems on Friday September 12, 2025 @03:33PM (#45225782)
Did you mean to type 25? 5 years ago LC challenge were as, if not more, prevalent than they are today. And a single interview for a job is not something I have seen ever after 15 years in the space (and a bunch of successful OSS projects I can showcase).

I actually have the feeling it’s not as hardcore as it used to be on average. E.g. OpenAI doesn’t have a straight up LC interview even though they probably are the most sought after company. Google and MS and others still do it, but it feel like it has less weight in the final feedback than it did before. Most en-vogue startup have also ditched it for real world coding excercices.

Probably due to the fact that LC has been thoroughly gamed and is even less a useful signal than it was before.

Of course some still do, like Anthropic were you have to have a perfect score to 4 leetcode questions, automatically judged with no human contact, the worst kind of interview.

Re:Qwen3-Next on Friday September 12, 2025 @09:38AM (#45222012)
People said the same thing for deepseek-r1, and nothing changed.

If you come up with a way to make the current generation of models 10x more efficient, then everyone just moves to train a 10x bigger model. There isn’t a size of model where the players are going to be satisfied at and not go 10x bigger. Not as long as scaling still pays off (and it does today).

Re:Defeating Nondeterminism in LLM Inference on Thursday September 11, 2025 @09:23AM (#45211319)
> I mean the mathematical idea of the standard LLM is certainly truly random.

Not really, LLMs give you a distribution over possible next tokens. You are free to then sample from this distribution how you want. There is no need to hack RNG or whatever, for example you can simply just take a greedy approach and always output the most likely token, in which case the LLM becomes deterministic (mathematically). This is equivalent to setting the temperature to 0.

Re:Defeating Nondeterminism in LLM Inference on Thursday September 11, 2025 @09:16AM (#45211253)
One of the top 5 most active contributors to pytorch over the last few years, and specifically working on some of it's most hardcore components is "just popular online"?

If you say so.

> the author has nothing to do with the original comment

Except for the part of the comment that was assuming the author had no idea how this all works, has only used LLMs through API and has never run a local model, you mean?

Re:Defeating Nondeterminism in LLM Inference on Wednesday September 10, 2025 @03:37PM (#45202559)
I suggest you look up the name of the main author of TFA before assuming they don’t know what they are talking about.

This is literally one of the most knowledgeable person on the topic. I think you are the one that hasn’t peeled enough layers to connect with what they are saying.

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