pizlonator

75 ms·

1291.
by pizlonator 5y ago
Interesting that it just reinvokes the whole function. I always thought that Wolfram does have some effects - like, you can print things. You can’t rerun the whole function if you have done any effects. But maybe I’m wrong about the effectf
1292.
by pizlonator 5y ago
Super cool to see a description of how Wolfram is compiled. I've used the Wolfram language for a long time but never really took a peak inside. Some thoughts: - The paper seems to suggest that compilation of scripting languages is not
1293.
by pizlonator 5y ago
I’m my view, Rust is a very uninspired kind of safe language. But a point on which I agree with Rust is that array accesses should be checked by default. I think this article ignores some arguments for array bounds checks and it ignores the
1294.
by pizlonator 5y ago
This is a great write-up! Makes me wonder if there is an alternative universe in which there is a syscall with semantics similar to mmap that avoids these pitfalls. It's not like mmap's semantics are the only semantics that we cou
1295.
by pizlonator 5y ago
JSC limits recompilation only in the sense that we have exponential back off on each jettison. But that means that a sufficiently hot function will keep getting recompiled forever even if speculation is permabroken in that function. Other t
1296.
by pizlonator 5y ago
The wasm blob has to undergo the hardest parts of optimization to get native code from it. You need to select instructions and allocate registers. Those things are time consuming; they are on the same order of magnitude of time consumption
1297.
by pizlonator 5y ago
What do you mean by exhausting jit caches? Do other VMs limit their size somehow? JSC basically doesn’t. That doesn’t solve the problem of course. I have this metric that I use to philosophize about this: SIPS, or static instructions per se
1298.
by pizlonator 5y ago
WebAssembly helps a lot, but doesn’t solve the jit issue. WebAssembly also introduces its own issues since it’s a BYORT system (bring your own runtime). So, there’s more to JIT (your language’s whole runtime) and more to hold in memory (you
1299.
by pizlonator 5y ago
Those are some really bad benchmarks. JavaScript is probably like 10x or 100x slower than C or similar languages when you write something bigger and any of the following happens: - the ratio of code size to run time is too big. Then the jit
1300.
by pizlonator 5y ago
I have no idea what you mean by fatalistic, and I don't think you're in a position to predict my thought process. Bugs exist because it is not possible for any one human or even organization of humans to know all of the ways in wh
1301.
by pizlonator 5y ago
This is so funny. I can’t even. It’s true that you can write code that has no bugs that would be relevant in a programming contest. And that you can avoid the kinds of bugs that you’d find if you read your code 2-3 times. But if you write c
1302.
by pizlonator 5y ago
You hit the nail on the head! And the same exact critique applies to folks saying “-Werror is harmful”. That statement is false unless you also add the limiting principle: “-Werror is harmful in software shipped as source that users build t
1303.
by pizlonator 5y ago
1. Make sure you know the right languages. A lot of great jobs involve languages that aren’t “hip”. C++, C, etc jobs are usually pretty great in terms of content. 2. Pick a sub field of CS that you like and do a personal project in that fie
1304.
by pizlonator 5y ago
For Sparkplug, bytecode is the input representation. But you’re right that bytecode is an intermediate representation of V8. So to me, whether bytecode is an IR or not depends on whether you’re talking about V8 as a whole or Sparkplug in pa
1305.
by pizlonator 5y ago
This is an impressive result! Congratulations are in order. :-)
1306.
by pizlonator 6y ago
They’re extremely useful in JITs where they arise all the time. WebKit’s JIT uses them about as frequently as an AOT like llvm would emit a relocation, maybe more.
1307.
by pizlonator 6y ago
In RISC, no, but I’m not sure it’s a hard and fast rule. RISC tends to allow addresses in the load/store to be exactly as complex as allowed by how many bits they’ve got available if you account for size of the architectural register f
1308.
by pizlonator 6y ago
This is really great, but RISC CPUs can have microcode too. Nothing stops them from doing that. The big diff is load/store: - Loads and stores are separate instructions in RISC and never implied by other ops. In CISC, you have orthogon
1309.
by pizlonator 6y ago
Witcher 3 told me what to do: buy flowers for the receptionist and then have a fist fight with the bank’s proprietor.
1310.
by pizlonator 6y ago
I feel like controlling naming is a great example of micromanagement. I mean, if in addition to manager you act as a code reviewer then as a code reviewer you might suggest a name. Or if you are an architect in addition to a manager and you
1311.
by pizlonator 6y ago
This is very likely true. There are other complex factors, too. I keep seeing polling/forecast methodology explainers mention calibration to historical data so that if the same method was applied to historical elections then it would h
1312.
by pizlonator 6y ago
Yeah exactly! And worth noting that these are just the ones where you usually have good sequences on other cpus, but even then (like signed mul) they’re not perfect. Lots of room for improvement. It’s just that risc-v didn’t seize the oppor
1313.
by pizlonator 6y ago
Arguably x86 only has a compressed encoding in the sense that super common instructions often fit in fewer than 4 bytes and some of the most used ones are 1 byte. I don’t think the compression is deliberate or optimal though.
1314.
by pizlonator 6y ago
I don’t think that beefier cpu and overflow checks are that related. I mean, you’re right, I just want to place some limits on how right you are. 1. Folks totally run JS and other crazy on small CPUs. 2. Other safe languages (rust and swift
1315.
by pizlonator 6y ago
Yes. In many ways: 1) it’s pretty important to have easy syntax for math with overflow checks. Otherwise there will be bugs. Bad bugs. We have those and it sucks. 2) it’s pretty important that if the overflow wraps in ISA then it wraps in l
1316.
by pizlonator 6y ago
First of all: I agree with you that the jury is out. We are all speculating. I might be wrong. The thing I see is this: you can also add compressed encodings for any ISA. And that has its own costs (it’s harder to decode and it’s harder on
1317.
by pizlonator 6y ago
One example of 3 is branching on 32-bit add overflow on a 64-bit cpu where you do a 32-bit add, a 64-bit add, and compare/branch on the result.
1318.
by pizlonator 6y ago
I mean you will do overflow checks on the following. I’ll use the “s” and “u” prefixes to mean signed and unsigned. Unsigned matters less than signed. sadd32, sadd64, uadd32, uadd64, ssub32, ssub64, usub32, usub64, smul32, smul64, umul32, u
1319.
by pizlonator 6y ago
I didn’t call it octagon when I wrote it because I didn’t know that I reinvented a shitty/awesome version (shitty because it misses optimization opportunities, awesome because by missing them it converges super fast while still nailing
1320.
by pizlonator 6y ago
That’s my suspicion too! I don’t think these folks have seen what modern languages do.

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