titzer

41 ms·

511.
by titzer 2y ago
I think about this a bit in the context of Virgil. Virgil's compiler is a whole-program optimizing compiler that does a lot of devirtualization and constant-folding. In the higher optimizations it does a bit of inlining, but I haven&#x
512.
by titzer 2y ago
> To me, speculation is where the fail path exits the optimized code. V8 is now doing profile-based guarded inlining for Wasm indirect calls. The guards don't deopt, so it's a form of biasing where the fail path does indeed go
513.
by titzer 2y ago
While better predictors allow the speculation window to be larger on average , the the real culprit is that large speculation window. Even if the branch predictor weren't very smart, it will still do well on a program with stable, pre
514.
by titzer 2y ago
Threaded dispatch is absolutely worth it. Wizard's interpreter gets anywhere from 10-35% performance improvement from threaded dispatch.
515.
by titzer 2y ago
These days I write nearly all my code in Virgil ( https://github.com/titzer/virgil ). It has features like classes, first-class functions, tuples, ADTs, unboxing, and a little data layout language, some unsafe features,
516.
by titzer 2y ago
> At the same time, higher-level languages sometimes can almost encourage the blindness to the real world model of computation, the execution implications be damned. In such languages you will encounter way more people who will write O(n
517.
by titzer 2y ago
I concur here. 20 years ago I was a JIT cheerleader and in the intervening time I've realized that you're only going to get the super-optimized hot inner loop perfect after the JIT and runtime has chugged through a ton of other sl
518.
by titzer 2y ago
> But the reality is that hand-optimized AoT builds remain the gold standard for performance work. It's considerably more complicated than that. After working in this area for 25 years, I have vacillated between extremes over decade
519.
by titzer 2y ago
Indeed, this was literally the conclusion of the first paper that introduced polymorphic inline caches. I'll add that the real benefit of ICs isn't just that compiled code is specialized to the seen types, but the fact that deopt
520.
by titzer 2y ago
Sure, that's not their job. It's the cultural shift we've allowed in the face of an overwhelming onslaught on our attention span.
521.
by titzer 2y ago
"In what way is it in my interest to give millions of my nation's money away to this filthy and corrupt justice system in an unwinnable fight against crime? I mean whether some mostly harmless serial killer offs two or three more
522.
by titzer 2y ago
It's a cultural problem that we let so much bullshit slide. America has come to love the spectacle, and loud wrong people can make quite a show. In a just society, there'd be a price to pay for lying. Free speech has consequences.
523.
by titzer 2y ago
We're not that far off from each other. > Just have the checker check the templates that the baseline JIT is stitching together Sure, from my second paragraph, the templates it's using could be opaque things it got from request
524.
by titzer 2y ago
This will kill baseline JIT performance. I am trying out a couple of new directions, e.g. generating more of the tiers from a more abstract description, constantly shrinking the amount of hand-written compiler/interpreter code. My hard
525.
by titzer 2y ago
In Virgil, native targets have a couple of unsafe operations available, one of which is to be able to forge a closure from a pair of a code pointer and an object reference. This is used, e.g. to implement Wizard's JIT and fast interpre
526.
by titzer 2y ago
Wizard's slow interpreter also runs on the JVM, albeit it very, very slowly. Have you done any benchmarking against Wizard?
527.
by titzer 2y ago
https://cheerpj.com/ https://thenewstack.io/cheerpj-3-0-run-apps-in-the-browser-w...
528.
by titzer 2y ago
Compiler backends are really complicated and a lot more difficult to debug than frontends. In my experience they account for more than frontend bugs.
529.
by titzer 2y ago
Indeed. C has such a loose spec, and so many behaviors are allowed under either "implementation-defined" or "undefined" behavior, that it devolves into finger-pointing pretty quickly. Most other languages have tighter sp
530.
by titzer 2y ago
America has a long history of not holding its political leaders accountable when they screw up massively. Gaslighting, obstruction, projection are pretty powerful tools.
531.
by titzer 2y ago
It is 100% Orwellian doublespeak. It should be a five alarm fire, but cowed media outlets are incapable of calling it out for some reason. Probably because they are terrified of the consequences. Preemptive surrender. Dark times ahead.
532.
by titzer 2y ago
The phrase you are looking for is "Orwellian doublespeak".
533.
by titzer 2y ago
> This reliance on the profit motive to enforce a Darwinian culling of private enterprises is a spherical cow. Absolutely. Large organizations tend towards self-preservative activities in the long run. One such thing is rent-seeking and
534.
by titzer 2y ago
> with armies of lawyers who’s job is to stall the process Absolutely, and that's just in a well-functioning justice system. Run that cycle through a few times, and the government finally realizes that fighting losing battles in cou
535.
by titzer 2y ago
> get punished Hard disagree on that one. Businesses calculate risk exposure and feign concern when forced (if ever) to pay fines after a lengthy legal battle in which the government goes up against extremely well-paid private lawyers th
536.
by titzer 2y ago
Well, I do know some people who really hate subnormals because they are really slow on Intel and kinda slow on Arm. Subnormals I can see being a pain for graphics HW designers. I for one neither love nor hate IEEE 754, other than -0. I have
537.
by titzer 2y ago
> Recreation and Parks Department rangers would cite him and tell him to move > The department’s environmental services crew...would tear down his tent when he was out and haul away his possessions. > For Barrows, trying to forcibl
538.
by titzer 2y ago
It's absolutely nuts to me that the government finds ways to spend money on literally anything but providing shelter, clothing, food, and support to people. UBI would be cheaper and far more humane than practically any policy--or lac
539.
by titzer 2y ago
Well since the linked page said nothing about it, I'll bite: Privacy is a check on tyranny and corruption. Some things you want to keep to yourself, even if they're not inherently wrong, illegal, or immoral: 1. Intimate moments wi
540.
by titzer 2y ago
IEEE 754 is what you get if you started with the idea of sign, exponent, and fraction and made the most efficient hardware implementation of it possible. It's not "beautiful", but it falls out pretty straightforwardly from th

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