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ahhon Benchmarking C++ Allocators

LTO I will grant you. I don't think you need to meaningfully inline the body of delete to get sized-delete to work effectively. You do want to statically link your sized operator delete body though, obviously. As of the last time I tried this, trying to inline the actual body was difficult to make effective, though.

(parent: read username :))

ahhon Stripe raises $600M at nearly $36B valuation

I should point out that the way you phrased it sounds very much like "Yeah, you're gonna carry a pager and like it. Deal with it." This, if true, entirely disqualifies Stripe for me as a potential employee; I am not interested in ever being on call, unless I'm getting an absurd slice of the upside that a company Stripe's size is not offering.

Do you want to clarify your phrasing or is that actually how you operate? :(

ahhon My favourite Git commit (2019)

I do love the social history of good commit messages, and what they teach us about the process of what we do.

I will offer one nit here, which is that I always start my commit messages with one-line summaries; this makes it really easy to scan commits (and git is tooled to do this!)

ahhon Why All of Our Games Look Like Crap

Somewhat off topic, but what's the closest thing to Avernum - a big, sprawly, kitchen sink RPG with a ton of backstory and fiddly combat - that I can play on my phone? (Not a tablet.)

Growing up Spiderweb games were some of my all time favorites and I'd love one on the go.

ahhon I was skeptical of unions. Then I joined one

It is when they're voting on how much a third party (I.e. you) will be required to pay them. See: the Chicago, California, and general us public pension crisis.

ahhon Eastgate Centre, Harare

Honestly? Good.

Architects and architectural styles are much more concerned with their particular artistic vision, and status signaling within their tribe, than with whether their buildings are pleasant to live within. (See: brutalism, for the worst case, but this applies widely.)

The more practical realities force architects to abandon their pet styles and build efficient places, the better. I have to live there; they don’t.

ahhon Eastgate Centre, Harare

They said that no direct sunlight must fall on the external walls at all and the north façade [direction of summer sun] window-to-wall area must not exceed 25%.

Pass. Natural light (and tons of it!) are a hard requirement for anywhere I actually want to work. (Besides light and airy spaces being generally pleasant, I have mild SAD.)

In any case, I'd rather use modern air conditioning, which is stunningly efficient. It also actually produces temperatures I can live in. They don't quote actual interior temperatures (or humidities!) but I'll bet their "acceptable" is 78F+. Anything north of 70 and I am a sweaty mess. (If you're cold, put on a sweater; I can't exactly strip in the office and you wouldn't want to sit next to me anyway!)

Complaints about air conditioning are mostly a form of modern self-flagellation. If you're not suffering, you're not doing enough for Gaia. Cost/benefit calculations simply don't enter into it (if they did, someone might point out that eliminating all cooling whatsoever would not even move the needle on US energy. Consider https://www.vox.com/energy-and-environment/2017/4/13/1526860... and https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1, from which you can see that cooling is 9% of electricity, which is perhaps 38% of total energy usage.)

ahhon Billions of Random Numbers in a Blink of an Eye

Fair, but rand() is kinda trashy, and the overwhelming part of that cost is fwrite anyway.

ahhon Coinbase is exploring the addition of new currencies

Less than a tenth of a billionth of my net worth: https://en.wikipedia.org/wiki/Kelly_criterion

ahhon Programs compiled by Go 1.11 allocate an unreasonable amount of virtual memory

Unreasonable according to you. :)

The nice thing about virtual memory is that it's, well, virtual. It costs you almost nothing until you've touched it. (Fun exercise for the reader: measure the kernel overhead for an unused 1 TiB VMA.) But creating huge spaces--that terabyte mmap wasn't theoretical--that stay untouched is hugely algorithmically useful, especially for things like malloc implementations.

Why does it bother people? Two reasons. First is mlock to avoid swap. This is solvable in much better ways--I'm a fan of disabling swap in many cases anyway. Second is that, absent cgroups, it's difficult to put hard limits on memory usage in Linux. So people, looking under the streetlight, put limits on virtual usage, even though that's not what they care about limiting! Then they get angry when you break it. My refrain here, as in many cases (see for example measuring process CPU time spent in kernel mode): "X is impossible" doesn't justify Y unless Y correctly solves the problem X does.

(I spent years in charge of a major memory allocator so this is a battle I've fought too many times.)

ahhon Amazon's Bezos Launches $2B Fund to Help the Homeless

Bezos pays the Danegeld. I'm disappointed in him. I'm also not sure what political player he's paying off...he didn't seem to need much influence with Seattle politicians lately.

Bezos is smart enough to know that the problem with Seattle homelessness has nothing to do with access to money. The city spends like water on the homeless, and we see nothing from it (which makes the spending a complete success for its intended beneficiaries, the bureaucrats in charge of the money.) We need a new policy to deal with them, and with this we won't get it.

ahhon Idle Thoughts About Pollard Rho

This is malformatted on my Android chrome--math is overlaying subsequent text :(

ahhon I usually run 'w' first when troubleshooting unknown machines

That actually seems like a great idea for a work sample test.

ahhon Meltdown Proof-of-Concept

> I don't see why that would have to add latency to all (or any) memory access. The addresses generated by programs (except in real mode, when everything has access to everything anyway so we don't care about these issues then) are virtual addresses, so they have to be translated to get the actual memory address.

L1 caches are generally virtually indexed for exactly this reason: to allow a L1 cache read to happen in parallel with the TLB lookup. (They're also usually, I believe, physically tagged, so we have to check for collisions at some point, but making sure there's no side channel information at that point is, obviously given recent events, hard.)

ahhon Intel Issues Updates to Protect Systems from Security Exploits

Flops are cheap. Bandwidth is expensive. Latency is physics.

We aren't at full lightspeed latencies ram technologies, but we're closer than you may realize, and it's unlikely we can do substantially better any time soon without revolutionary advances.

ahhon LLVM patch to fix half of Spectre attack

I don't know any way to leave enough breadcrumbs to do that in four clock cycles, do you?

ahhon Call of Duty gaming community points to ‘swatting’ in Wichita police shooting

I think the police are smart enough to realize that Police 2.0, whatever you call them, are intended to replace them.

ahhon FreeBSD – a lesson in poor defaults

I'm uncertain if it's safe to use AESENC and friends in kernel mode in Freebsd. A number of kernels can't safely use e.g. FPU registers in-kernel and aesni operates exclusively on SSE state.

ahhon By ditching usernames, OKCupid is removing a crucial protective barrier

> if higher quality men have more of their time wasted... if the men who write detailed messages get worse results than the men who write a thousand identical one-liners (or who swipe right on everything, etc.), then the former type of men will leave the site and women will be left with the latter type.

Yeah, that's not what makes a man "high quality" by the data and revealed preferences online. Attractiveness does. The men any woman wants to see on a dating site online don't have their time wasted, because they get responses to whatever they write.

ahhon Don’t keep cell phones next to your body, California Health Department warns

If you discovered a mechanism by which it was possible for a cell phone to cause cancer, you'd win a Nobel Prize in physics.

Not "you discovered that they did, in fact, cause cancer"; just discovering a way that it is physically possible for them to do so.

This dates back to Einstein's explanation of the photoelectric effect: it's easy to show (and the only thing consistent with all of 20th century physics!) that light can only cause molecular damage if individual photons carry enough energy, which in turn only happens if the radiation is of sufficiently high frequency (like UV light, X-Rays, or gamma radiation.) Any radio signal from a cell phone isn't. End of discussion.

Unless you are being actually cooked by a microwave, your cell phone does not and cannot cause cancer.

"Radiation" is a scary word for non experts, but the California Health Department should know better.

ahhon Show HN: Tax plan impact calculator

> It takes in to account state taxes

Wildly incorrectly. I live in WA and it overestimates my sales tax deduction by a factor of ten.

ahhon CVS Is Said to Agree to Buy Aetna

I wonder if this will lead to restrictions on the use of copay coupons [1]. Insurers hate them since they break my incentive to use cheaper drugs from their formulary, but pharmacies don't care (and probably are better off for me using them.)

Since I mostly hate my insurer and want to help them towards bankruptcy by extracting as much coverage from my fixed premium as possible, I have no objection to using these coupons if they'd help me and I felt like an expensive drug choice was better for me, though it's not come up for almost any drug I've needed.

Though I do need new epi-pens; maybe I should look for one while I still can!

[1] https://www.propublica.org/article/are-copay-coupons-actuall...

ahhon Physicists make most precise measurement ever of the proton's magnetic moment

(Disclaimer: not a QCD expert, but I did read a paper or two back in grad school from the perspective of someone who liked numerical linear algebra. Don't rely on this advice.)

I believe the core difference here between QCD and QED (the classical perturbative QFT) is that QED has a very small coupling constant (it's the fine structure constant, so ~1/137) whereas QCD has a large one (comparable to or greater than one.) It turns out that a perturbative expansion is effectively in powers of the coupling constant, so QED expansions converge rapidly...and QCD expansions converge not at all.

ahhon Stack Overflow Salary Calculator

I don't think the Stack Overflow data is fantastic, but I'm not clear that the BLS stats are any better for the fancy credentials of their collectors.

In either case, the problem is coming up with a reasonably accurate reference class. At least in my case, I'm not well represented by the BLS breakdowns (which underestimate what I can expect to get by a factor of about four.)

The Stack Overflow approach, using industry-specific features (developer-friendly keywords/job titles/languages) is definitely smarter, though still wildly insufficient. (It's only off by a factor of about three.)

ahhon Computer Randomly Plays Classical Music (2009)

A while back I was playing Half-life on Steam, and every so often a classical madrigal would start playing, with oddly familiar voices. A truly strange bug; I couldn't think of any good reason for it.

Months later, I opened my computer's DVD drive for once, and discovered the reason: my sister, a professional classical singer, had sent me one of her recordings, and I had put it in the computer to listen and forgotten about it for the next year.

Somehow the game was--from its original on-cd release--assuming the proper soundtrack was on track N of the CD, instead of the Steam install.

Remarkably simple in the end, but a very baffling bug at first.

ahhon Read This Before You Build Uber for X

This is pretty interesting and apt. One thing I'd quibble with is their claim that many professional skills aren't fungible; this is true in general but there are many cases where a non-fungible skill is fungible for a major use case.

In particular I'm thinking of doctors. I care a lot about having exactly the right doctor (a good one, a specialist, etc) much of the time, but there are many medical services where I simply need anyone competent to pass their boards with a prescription pad. (I have been taking the same three or four prescriptions since I was six for a few common ailments--I don't need someone to tell me special information about albuterol.)

ahhon Dangers of Sitting

I can pull twice my bodyweight, actually.

ahhon Dangers of Sitting

I know this well, but standing for more than about an hour is torture on my back. (I suspect my flat feet and tight hips contribute here.) I have no idea how to fix this.

ahhon On Melissa O’Neill’s PCG random number generator

ACM Transactions on Mathematical Software.

ahhon How I, a woman in tech, benefited from sexism in Silicon Valley

Whether or not this is in dispute, what you're doing here is injecting Trump and an inevitable culture war about him into a thread that's already likely to be contentious.

Unless Trump has specific relevance to this dispute, which I don't think he does, bringing him up is going to just add heat and fuel, not understanding. I think the mods would rather you didn't.

Just a thought. :)