Do you know how I can edit the tags? Or do the mods have to? Couldn’t find the option :(

Yeah, after some reading it seems to be due to dead store optimization.

If the memory is not accessed after you store something there (i.e., memset), the compiler will reorder the instructions and the dead store is removed.

There was some interesting discussion on GCC’s bugzilla about this. Is that a bug or not? I think it is.

After some Googling I found the explicit_bzero function that @kristapsdz mentioned, but the glibc version. The trick it uses is to add asm volatile ("" ::: "memory") after the memset call. That prevents any stores prior to that point to be reordered.

There’s also Nils M Holm’s books: http://t3x.org/

There are a lot of books on compilers, but not as much for interpreters (i.e. the bytecode compiler + dynamic runtime combo that many languages use).

Not a book, but you still might find this paper interesting: Engineering Definitional Interpreters:

Abstract: A definitional interpreter should be clear and easy to write, but it may run 4–10 times slower than a well-crafted bytecode interpreter. In a case study focused on implementation choices, we explore ways of making definitional interpreters faster without expending much programming effort. We implement, in OCaml, interpreters based on three semantics for a simple subset of Lua. We compile the OCaml to x86 native code, and we systematically investigate hundreds of combinations of algorithms and data structures. In this experimental context, our fastest interpreters are based on natural semantics; good algorithms and data structures make them 2–3 times faster than interpreters. Our best interpreter, created using only modest effort, runs only times slower than a mature bytecode interpreter implemented in C.

it really is beyond the pale of what I would consider possible in a professional work environment.

I’m really glad she kept with it after the blowback she got!

I wonder why we don’t hear these “horror stories” as much from HR folks (who presumably have far more visibility of them than engineers!) as often, but I suppose that it’s probably a much bigger career risk to call out this stuff publicly when your job description is basically to deal with all of it and make sure it doesn’t become a legal or PR issue.

One may wonder how Bob Coe would have found assistants if this was a 100% encouragement or direct order. Good thing we moved from boys-will-be-boys to disgusting, otherwise someone could really use this as a guideline in recruitment!

It is already merged into upstream, thanks! :-)

yeah. I suspect better article naming would be better at not leaving people feel like they kept on expecting the article to go somewhere it didn’t.

Maybe “all platforms” means all versions of Windows, most OS X, and latest Debian stable.

I sincerely don’t understand this hate against Microsoft.

Yeah sure, Ballmer days sucked and they really screwed up. But since Natya picked up the role, there seems to have been quite a shift in the company’s mindset. Plus all the OS things they’ve been doing in the past few years.

That’s a description of what they want to extend and eventually extinguish.

Thanks very much for your pointing out to use mdoc!

Compared to vmstat(8), my simple toy has following differences:
(1) Add displaying swap space;
(2) Only consider active pages as “used” memory, others are all counted as “free” memory.IMHO, for the end user who doesn’t care the guts of Operating System, maybe this method is more plausible?

All in all, I just write a small tool for fun, and thanks very much again for giving pertinent advice!

Thanks for educating me about the distinction: https://github.com/blinkkin/blinkkin.github.com/wiki/man-vs-mdoc

Hyperspec is complete, but it is in no way pleasant to use.

Funny, I find myself missing the Hyperspec every single day (I now write mostly Clojure). It remains the standard against which I judge most other documentation. (And I’m not sure what you mean when you say it doesn’t have examples; the Hyperspec page for defstruct has over a dozen separate examples of different uses.)

Yes, it’s unfortunate that there is no realistic way to change or grow the language, but as far as documenting what does exist in the standard the Hyperspec does a great job.

That’s fair, but Ruby’s performance is on par with Python’s (or better in at least some benchmarks, actually), which is plenty good enough for many, many people. So for those using Ruby, that’d still be an incredibly welcome improvement.

That said, I’m curious when you last tried Ruby. It’s definitely still an order of magnitude slower than most compiled languages, no question, but the new GC that landed around 2.2, and the bytecode based VM that landed around 1.9 or so, have made a huge, very noticable difference in places I’ve used Ruby. It’s been enough that I’ve kept reaching for it over e.g. Go in quite a few instances.

The upcoming support for guilds is much more exciting in terms of addressing new problems than single-threaded execution improvements, IMHO.

A less humble opinion of mine is that guilds are too little, too late, and still too primitive to have a transformative effect on Ruby and its ecosystem. I think too many devs (like me) are now accustomed to more advanced/higher-level concurrency abstractions, and guilds feel like a slightly safer way of revisiting the mid-90’s.

It’s used a whole lot in web dev so 3x faster will make a lot of websites faster.

I think it just helps people who have already invested in Ruby justify their continued investment. I wouldn’t expect a ton of new users at this point unless they develop another “rails”.

What are your favorite languages?

In this particular case, it feels like the code isn’t too far from what C code would be: here are some basic data structures and here are some functions that operate on them, mostly on the bit level. No fancy concurrency models nor exciting constructs. I think given the fact that this is an inherently low level program, most nicieties from Go weren’t immediately needed.

I did use some inner functions/closures and hash maps, but could’ve just as well done without them. The bottom line is that the language didn’t get in the way, but I didn’t feel like it was enourmously helpful, other than making it easier to declare dependencies and handling the build process for me.

Interested in this as well. I’ve toying with the idea of writing a CHIP-8 emulator in Go and would love to hear about how is the experience of writing emulators.

To me the first obvious drawback of optional<size_t> is that it doubles the size requirements. On 64bit machine this will typically grow from sizeof(size_t) == 8 to sizeof(std::optional<size_t>) == 16.