[HN Gopher] Forcing Flash Attention onto a TPU and Learning the ...
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Forcing Flash Attention onto a TPU and Learning the Hard Way
Author : azhng
Score : 26 points
Date : 2026-03-08 03:57 UTC (4 days ago)
(HTM) web link (archerzhang.me)
(TXT) w3m dump (archerzhang.me)
| gdiamos wrote:
| One of my lessons in using different accelerators, whether they
| be different NVIDIA versions, or GPU->TPU, etc is that someone
| needs to do this work of indexing, partitioning, mapping,
| scheduling, and benchmarking. That work is labor intensive.
|
| In this case, google has already done it, and that will be true
| for high resourced accelerator companies like Google working with
| the most popular operations like attention.
|
| As long as you use those operations, you are okay. But if you do
| something different, you need to be prepared to do all of this
| yourself.
| refulgentis wrote:
| It broke my heart to have a visceral "I'm being slop'd" reaction
| reading this: it's _such_ good work, and AI 's barely used
| AFAICT, but there's enough odd transitions and copy-pasta'd
| markdown that you get the subconcious "this is AI" reaction
| regardless.
|
| Many sentences are 3x as long as it normally would be in subtle
| ways (to wit: "My flash attention is 35x slower than the fused
| standard at n=4096. Not a little worse. Catastrophically
| worse."), it really wears on attention. (pun intended) It brings
| literary voice to a technical blog post, and a very difficult
| process-oriented technical blog post. I have to reallocate my
| unfortunately-limited brain cells from "maintaining state of
| where we are in the process" to "is this cutesy fluff or
| important" and I've never had to do that in 37 years with
| technical blog posts.
|
| The Markdown gets _bad_. Bolding is used for important phrases
| (like a human would), then, all of a sudden, after the "Inside a
| TPU chip" header its being used every other sentence, on anything
| that is a proper noun/would have a Wikipedia article. It got so
| weird that at some point I was like "a human _definitely_ didn 't
| let this through...they must be links?" and tried clicking them.
|
| It's doubly bad at that point, because markdown tables start
| coming in hot and heavy too. So you're left with "It's pretty
| apparent the LLM did it from here, and I can't keep trying to
| keep the state of the process in my head while trying to figure
| out if the bolding is important, _reflexive close tab_
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