sharpneli

8 ms·

121.
by sharpneli 6y ago
http://backreaction.blogspot.com/2017/01/the-bullet-cluster-... And same thing applies to LCDM. How does it explain bullet cluster, and several others, existing in the first place? Disclaimer: I'm not a cosmo
122.
by sharpneli 6y ago
Yap. And ARM has the advantage of requiring a smaller frontend. Especially when one looks at wider decoders. On the other hand if your ISA is the micro-ops directly then the instructions start to take ridiculous amounts of space. It's
123.
by sharpneli 6y ago
It took about 10 years for x86 to go to zero marketshare in servers into 80%+ in the 90's. Similar change in HPC market etc. So based on history the transition time is around 10 years, not tens of years.
124.
by sharpneli 6y ago
And M1 does the same. All modern CPU's are really similar internally in that sense. ISA is just a frontend that gets translated into micro-ops that then get scheduled based on dependencies and available execution ports. Even the regist
125.
by sharpneli 6y ago
> Nobody wanted the x86 ISA unless they needed it in systems which ran legacy applications. It wasn't fast/efficient enough. If it had been faster or with better power consumption it would've been fine. There was a massive
126.
by sharpneli 6y ago
Really? That’s more money than we use for the unemployed here in Finland. And they get healthcare, food and house. SF is expensive for sure, but that expensive? Where is the money going to?
127.
by sharpneli 6y ago
The original post talked about this causing a lack of discovery for the new music. If the streamer doesn't pay and just uses non-copyrighted music no harm done to the streamer. It's still great fun. But the users don't get ex
128.
by sharpneli 6y ago
Good point. So they simply were not able to ramp up faster than it took for the existing manufacturers to start catching up and leveraging their scale better.
129.
by sharpneli 6y ago
One can perhaps think of this as Teslas blind spot. People living with California wages don’t necessarily see the difference in prices mattering that much.
130.
by sharpneli 6y ago
> On your remark about char*, it is an universal type alias, but I don't think it is an universal provenance alias C doesn't have a concept of provenance in this fashion, or alternatively the compiler must assume the pointers m
131.
by sharpneli 6y ago
I'm pretty sure there is no UB in the second part. It's just LLVM bug. The pointer comparison is valid (pointer to and object and to an another object that's one past the end MAY compare equal). The write is valid. Reads and
132.
by sharpneli 6y ago
Large part yes. But not The reason. It’s fast because of many things like that. TSO doesn’t affect single core perf much so it’s not really a factor there, and yet it’s blazingly fast. However the multicore perf is really great too. I haven
133.
by sharpneli 6y ago
Having to appear worked that way does cause restrictions in multiprocessor case. ARM chips naturally do all of that too, with the memory model simply giving them way more freedom to reorder things. One couldn’t do X86 version of M1, mostly
134.
by sharpneli 6y ago
It has to flush them. Because if another core sees the result of the atomic op it must also see everything else that the other core wrote before the op. While it can indeed first see no writes and then suddenly all it can never see just the
135.
by sharpneli 6y ago
Yeah they did. Substantially https://www.google.fi/amp/s/cbslocal.com/2018/01/31/despite-... ” Cell phone robberies and thefts from persons went down 50 percent in the first two years after the
136.
by sharpneli 6y ago
Another major difference is the memory model. In X86 other CPU’s must always see the writes of a core exactly in the right order. This limits the ability to reorder store ops significantly. ARM requires a memory barrier for this. This is a
137.
by sharpneli 6y ago
> Already every mac available for purchase, even the Intel ones, requires online activation to wipe and reinstall the storage There is a massive practical upside of this. It makes thefts worthless, or almost worthless as the only value i
138.
by sharpneli 6y ago
Non-competes are illegal in California. That’s likely a big reason why it is so successful. As an example neither Intel not AMD would exist if non-competes would be allowed there. Iirc Nvidia too.
139.
by sharpneli 6y ago
This was news for me. Thanks for pointing this out. Makes sense to have cocaine at Schedule I. Still, having Cannabis at Schedule IV is funny.
140.
by sharpneli 6y ago
So wait. According to UN cannabis was more strictly limited than cocaine? Based on perusal on the drug categories before this change one could get prescription of cocaine but not cannabis. This is absolutely hilarious.
141.
by sharpneli 6y ago
That's why I tried to use it more as a methaphor. Because the whole point of explicit VLIW (EPIC was what Itanium folks called it) was to save that scheduling HW. But nowadays that piece of HW is relatively minor part. So it's no
142.
by sharpneli 6y ago
That's a great point to emphasize. Because memory access times are inherently more or less nondeterministic. I consider it to be roughly as important as being able to reorder instructions across non statically determined branches and f
143.
by sharpneli 6y ago
The current CPU's already are VLIW in a fashion. Its just that they have a hardware jitter for it. That's what superscalar OoO CPU basically is, a piece of HW that generates VLIW instructions based on the normal instructions that
144.
by sharpneli 6y ago
It depends. In case of Artificial leather it refers clearly not to lab grown animal skin but to a completely different product that just tries to emulate leather. So the word is used in different contexts. And De Beers is more than willing
145.
by sharpneli 6y ago
> It does, but you can always disassemble the DXBC and see what happened to your HLSL code. And you can always disasm X86 code and see what -ffast-math did. Doesn't mean that everyone would be fine with just mandating it everywhere
146.
by sharpneli 6y ago
Compiler does the reordering. Not the GPU itself. Even in OoO CPU’s the ordering by HW doesn’t affect FP results. As a rule of thumb shaders in graphics are compiled as if one had passed -ffast-math to the compiler. Works perfectly in most
147.
by sharpneli 6y ago
Basic fp ops like +-*/ are fine generally. It's more about the ability to prevent reodering of instructions (so that Kahan summation etc is not screwed up), and having well defined spec for the precision of things like transcenden
148.
by sharpneli 6y ago
That's just compute shaders in DirectX. They also support compute shaders in Vulkan and OpenGL. It's not exactly the same as Cuda and OpenCL. Especially the numerical precision requirements are way off on graphics apis. And by way
149.
by sharpneli 6y ago
Quick perusal of the extension would indicate that it’s main purpose is to help emulate dx12 more efficiently. DX12 doesn’t have descriptorsets like Vulkan. It has descriptorheaps that are bit different. This extension basically makes them
150.
by sharpneli 6y ago
Linux is written in C. In C99 and later type punning trough unions is well defined operation. No issues there. It’s C++ that’s lacking this feature. Not C.

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