[HN Gopher] Apple M1 Microarchitecture Research
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Apple M1 Microarchitecture Research
Author : my123
Score : 148 points
Date : 2021-03-07 11:49 UTC (11 hours ago)
(HTM) web link (dougallj.github.io)
(TXT) w3m dump (dougallj.github.io)
| mhh__ wrote:
| Source for what a validation buffer is? Couldn't find a reference
| on google
| sesuximo wrote:
| They say the M1 may use a validation buffer instead of a re
| order buffer. This makes it somewhat clear if you know what a
| re order buffer is.
|
| Processors basically do this: read instructions, execute them
| out of order to fully use cpu resources, put the instructions
| back in order along with their results, and then write results
| to memory. This way the "final state" follows the order of
| instructions.
|
| The "put back in order" step is handled by the re order buffer.
| It is basically an online sort algorithm.
|
| Fully sorting instructions after execution is simple and
| correct, but in extreme cases may be suboptimal; perhaps it
| doesn't matter if the final state is exactly in order or just
| close to that. I believe the article is saying the M1 may just
| validate states as they are written rather than fully
| reordering.
| mhh__ wrote:
| It was the distinction between validation and re-order that
| confused me.
| algorithm314 wrote:
| Probably this
| https://www.researchgate.net/publication/250780982_The_Valid...
| [deleted]
| black_puppydog wrote:
| Hats off to people who do this kind of work. However... *clears
| throat*
|
| I have real trouble using the term "research" for something like
| this, lumping it together with activities such as "research" in
| natural science, "research" in anthropology, or even journalistic
| "research".
|
| The difference to me is that this activity could be "done", or
| rather entirely avoided, if Apple didn't decide to keep it a
| secret.
|
| Mind you, I'm not saying Apple doesn't have good reasons to keep
| them secret, for some definition of "good". I just think that
| this person just spent hours upon hours of their life working
| around a quirk in our current society.
|
| I'm aware I'm splitting hairs, but "we don't know what the
| architecture is" to me is fundamentally different to "we don't
| know what dark energy is." The former is something that could
| "easily" be changed, the latter is not. Lumping them together
| just cements the idea that the systems we built and navigate, for
| better or worse, are to be treated like natural laws that can't
| be argued with.
|
| /rant
| mindvirus wrote:
| Your comment reminds me of a scifi story (Greg Egan maybe?)
| where AI has taken the lead on science, and humanity's
| scientists' job is now just to understand the AI's discoveries.
| guerrilla wrote:
| Research you don't like is still research.
| koolkat666 wrote:
| lots of journalistic research is also about uncovering secret
| knowledge and information, for example classified government
| documents, corporate cover-ups and various forms of human
| rights violations. you are right tho, that with more
| transparency and less predatory legal constructs the jobs of
| both journalist and computer researchers would be way easier.
| glangdale wrote:
| That's a weird take. Journalistic research, for example, also
| often involves bringing to light facts that some in-group
| already knows. The word research is a lot broader than what you
| claim; people talk about "researching" which television set to
| buy, and everyone understands what they mean.
|
| So your contribution here is "this guy is figuring out stuff
| that people at Apple already pretty much know". Err, thanks,
| Captain Obvious.
| guerrilla wrote:
| Security research could be considered another similar
| example.
| mensetmanusman wrote:
| Think of it as approaching the topic from the other side. It is
| very analogous to what security researchers to.
|
| Consider things like the incompleteness theorem, and how there
| will always be gaps in our implementation of a given
| epistemology, in this case computer science, hoping to achieve
| a given end.
|
| Researchers then look at that output while entirely blind, and
| then they work backwards, and they can sometimes uncover very
| useful insights that the original creators may have been blind
| to.
| gumby wrote:
| I understand where you'd coming from and also do a double take
| when I read this term, though I think it's legit.
|
| Consider: what does an agency that spies on other countries'
| governments do? Research?
| monocasa wrote:
| Just because other humans created the knowledge in question,
| doesn't make the search for that knowledge not research, if the
| knowledge isn't held by the general public in the first place,
| and if that knowledge requires independent gathering of data
| and interpretation to acquire.
|
| I agree that Apple and the quirks in our society that encourage
| that secretive behavior has the effect of researchers
| independently replicating a small subset of Apple's work in a
| way that they'd be redirected to something more useful in a
| more open society. That doesn't make the independent
| researcher's work not research though.
|
| Otherwise nearly the whole field of anthropology wouldn't exist
| or wouldn't be considered research.
|
| > Lumping them together just cements the idea that the systems
| we built and navigate, for better or worse, are to be treated
| like natural laws that can't be argued with.
|
| The systems we have built are pretty fixed in time. We can
| argue about how to change them going in the future, but we
| should also record, externally if need be like here, what has
| happened so that we can make better decisions going forward.
| Apple's choices for the M1 are arguably more set in stone than
| our conception of physics. We're able to retcon all of physics
| when we make changes to the standard model, but "what tradeoffs
| did Apple make in the M1" are pretty much done and set in stone
| (or silicon I guess).
| njitbew wrote:
| The distinction you're making is more about _fundamental_
| research vs. _applied_ research, but it is research
| nevertheless.
|
| From the first hit I found on Google:
|
| * Fundamental researches mainly aim to answer the questions of
| why, what or how and they tend to contribute the pool of
| fundamental knowledge in the research area.
|
| * Opposite to fundamental research is applied research that
| aims to solve specific problems, thus findings of applied
| research do have immediate practical implications.
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