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Apple CPU tricks: memory reordering, JavaScript support, ref counting

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Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#161
post #101

Earlier quoted context omitted.

The Swiss watch industry isn't what it was. Most people I know don't wear a watch.

Wait, where did the goal posts go. Has anyone seen them? I swear they were here a minute ago.

The goalposts were with widely used computing devices this entire time, but some people want to move them next to typewriters and watches.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#162
post #121

Earlier quoted context omitted.

To be fair to the person you're responding to, the goalposts look to have been "disrupt a large existing industry." "Large" is obviously subjective, but if the example of the disrupted industry is the watch industry, "the watch industry isn't large so it doesn't count" is a reasonable response within the constraints of the original goalposts.

I suppose so, but who was saying this in 2014 and 2015 when the other smart watches were out and Apple's offering was only a rumour? Back then the consensus was the watch would be a watershed test of whether the team at Apple had it in them. Now that they've conclusively nailed it, we discover it didn't count after all. Of course the expectation was that the Apple Watch should be just as popular as the iPhone and tra…

> who was saying this in 2014 and 2015 when the other smart watches were out and Apple's offering was only a rumour?

I was and still am. As I said, most people I know don't wear a watch, myself included. It was the same in 2014 and 2015.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#163
post #145
post #97

Earlier quoted context omitted.

If Apple is free riding on how great ARM is, how come everybody else’s mobile ARM chips are such pants in comparison?

You (and apparently most of HN) is misunderstanding me: I’m not saying Apple isn’t doing great stuff or that they’re just coasting on ARMs tech, but it is the ARM ISA that enables them to make the M1 so ridiculously good. But people won’t believe that and will attribute it to Apple’s vertical integration until they are holding a Windows laptop with an ARM CPU and crazy battery life, thermals etc. And again: ARM alrea…

No, we understand fine; we disagree with the claim that M1 is good because of the ARM ISA. Had Apple picked something else a decade ago we’d probably see them pulling ahead with that, too.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#164

It’s important to note that most of the things mentioned here are just “tricks”: they’re fun to discover and talk about, but they really only end up being minor wins in practice. TSO is great…if you are trying to make a simpler Rosetta (it’s not even necessary on the M1, although I think Apple is still using it for convenience; I’m still trying to find out where). The JavaScript instruction speeds up…one specific rou…

I disagree regarding the importance of this kind of "tricks". You are right in pointing to all the "boring" stuff that is considered state of the art in chip design being the main reason why these chips are impressive. Apple seems to have pulled all the right strings in that regard. But there is a point at which you can't execute the known optimizations any more perfect than you already do - when you're already using…

The point is that in benchmarks these things don’t really show up at all and Apple still leads. The things I mentioned are only useful because of specific usecases, and saying that Apple is ahead because of those is inaccurate. The point is that the tricks are extremely important for Apple, but not in an argument of “why is Apple making fast processors”.

Regarding a comparison with AMD: I think we’ll have to see what Apple’s professional chips can do. My guess is they’re pulling ahead already.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#165

It’s important to note that most of the things mentioned here are just “tricks”: they’re fun to discover and talk about, but they really only end up being minor wins in practice. TSO is great…if you are trying to make a simpler Rosetta (it’s not even necessary on the M1, although I think Apple is still using it for convenience; I’m still trying to find out where). The JavaScript instruction speeds up…one specific rou…

"Tricks" makes great difference in life. I can jump over a meter high with my bicycle because someone who knew did teach me the "bunnyhop trick". That and other "tricks" give you the ability to do things save on a bicycle that most people consider impossible or too risky. Knowing the tricks of a trade, like software development, means the difference between starving or success. In the same way there are "tricks" that…

I know exactly why these things exist: it’s because they serve specific strategic interests that Apple has. They aren’t how the processor is getting great single-core scores on Geekbench.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#166
post #133

It’s important to note that most of the things mentioned here are just “tricks”: they’re fun to discover and talk about, but they really only end up being minor wins in practice. TSO is great…if you are trying to make a simpler Rosetta (it’s not even necessary on the M1, although I think Apple is still using it for convenience; I’m still trying to find out where). The JavaScript instruction speeds up…one specific rou…

The most informative post at the moment for me, with more detailed technical information for those who are interested in what's actually making Apple's M1 CPU fast, based on the article by Anandtech, is much lower on this page, by GeekyBear: https://news.ycombinator.com/item?id=25235214

The AnandTech article is not bad, but I have heard that their tests misrepresent some microarchitectural details that they didn’t manage to guess the underlying design of correctly.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#167
post #85
post #44

> 4/ So Apple simply cheated. They added Intel's memory-ordering to their CPU. When running translated x86 code, they switch the mode of the CPU to conform to Intel's memory ordering. Uh, no. Implementing TSO in a highly performant way is not "cheating", it's a difficult engineering feat. And no, TSO is not some fancy Intel thingy. It's a standard memory model.

To add to this: The POWER7 through POWER9 processors from IBM implement an equivalent to this called "SAO", or "Strong Access Ordering Mode". To quote an IBM engineer: > Currently, power has a weaker memory model than x86. Implementing a stronger memory model allows an emulator to more efficiently translate x86 code into power code, resulting in faster code execution. What's interesting is IBM publishes pretty detail…

On the M1 this should work on any core.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#168
post #108

Earlier quoted context omitted.

Apple Watch put a Unix computer with a 16-hour battery life, an LTE modem & multiple health sensors on my wrist. I’d count that as significant.

Where are the UNIX APIs on watchOS? Having fun with writing CLI apps and daemons for the watch? Plus POSIX support in IoT like devices exists since ages.

watchOS lets you call much of the UNIX APIs, you (as third-party developer) just aren’t allowed to make command-line tools and daemons.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#169

Earlier quoted context omitted.

Very unlikely that IBM would have used the 8088 without a second source - so literally Intel needed firms like AMD.

Not unlikely, it was a condition.

Nope, it was a condition from government to buy PCs from IBM, most of their computers have always been single source.

Re: Apple CPU tricks: memory reordering, JavaScript support, ref counting

#170
post #153

Earlier quoted context omitted.

What? I was there on the early days, that just makes no sense. Cyrix, VIA and friends were ocean drops, hardly available outside US.

Very unlikely that IBM would have used the 8088 without a second source - so literally Intel needed firms like AMD.

So what were the second source from all major IBM computers throughout its history?
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