rwem

5 ms·

1.
by rwem 7y ago
The air pollution in Pittsburgh isn’t caused by things under the control of the local government or even the state government. It accumulates and blows in from west of there. Only the US federal government can fix it.
2.
by rwem 7y ago
I reached the same conclusion but luckily before moving there. Pittsburgh just has bad air. It also has the least sunlight of any American city.
3.
by rwem 7y ago
The graph is electric generation only. Electricity accounts for less than 1/3rd of US greenhouse gas emissions.
4.
by rwem 7y ago
They’re not steadily falling. As noted in the article, they were up in 2018.
5.
by rwem 7y ago
I get the impression from the map of responses that many respondents were taking the piss. Who really thinks Iran is Greenland?
6.
by rwem 7y ago
Because we’re all idiots and waited too long, we need to cut emissions by 15% annually, not 2%. 2% does not even offset the increase in US emissions in 2018. 2% is a disaster.
7.
by rwem 7y ago
"We need labels that strike at the heart of each issue" That's pretty much the opposite of the "housing first" approach.
8.
by rwem 7y ago
Why do Americans [anything]? Because in short they are ignorant. Americans lack perspective on virtually all topics. They don't read enough, they don't travel enough, their educations are overwhelmingly technical and occupational
9.
by rwem 7y ago
The implementations in the benchmark are all pretty naive. You might get a different outcome with more careful implementations of the functions.
10.
by rwem 7y ago
I imagine the downvoting is due to your erroneous projection of the customs of your locale to the entire larger world. Even narrowly considered, your links don’t really support your point of view (eg there are numerous shared pedestrian&#x2
11.
by rwem 7y ago
Thank you for sharing the customs of your people and/or jurisdiction.
12.
by rwem 7y ago
Guess I'll just stick with the air horn.
13.
by rwem 7y ago
The killer application for this technology is a bicycle bell you can use to break the trance of phone-staring pedestrians who are randomly staggering down the pavement.
14.
by rwem 7y ago
Yes, and sometimes you want to validate a performance change and you need the release build to run in the benchmark fixture, and then it's irritating that the build takes forever but what can be done? ThinLTO's real benefit is tha
15.
by rwem 7y ago
Everybody should build everything with a reasonable setting of march. Debian Linux still builds everything for K8, a microarchitecture that lacked SSE3, SSE4, AVX, AES, etc. Even building with march=sandybridge seems petty conservative and
16.
by rwem 7y ago
ThinLTO was written by people responsible for peak optimization of very large programs at Google. I honestly can’t call it “fast” but it’s a lot faster than GCC LTO. You normally only peak-optimize your release builds so it’s not like devel
17.
by rwem 7y ago
Power limits have the same problem, don't they? Except it's maybe worse because you get the product of the error terms for Icc and Vcc?
18.
by rwem 7y ago
I wonder how much of this is due to measurement error of temperature. Core frequency and voltage control are governed by some suspiciously round numbers like Tj(max) == 90C. But when the controller thinks Tj == 90C, what's the measur
19.
by rwem 7y ago
See that’s the kind of information I want to surface in an interview: candidate thinks C++ doesn’t have random-access iteration. No hire.
20.
by rwem 7y ago
SunRay were not Solaris-only. In fact virtually all of the ones that sold were used as Windows terminals.
21.
by rwem 7y ago
You'll probably get a lot more benefit from just pulling up powertop and fixing whatever dumb thing is eating your battery. Common issues that are never right by default are PCIe ASPM, SATA ALPM, audio codecs that are always powered,
22.
by rwem 7y ago
Seems to have some control loop deficiencies. If CPU utilization is ~50% then it will enable turbo and utilization will fall below 50% and then it will disable turbo again.
23.
by rwem 7y ago
Is this the kind of thing they are asking in interviews these days? I guess it is nice that this author can prove the correctness of their solution, but what's up with that code? Why is what would otherwise be a perfectly good free f
24.
by rwem 7y ago
If you only have 4 threads it is likely that all your CPUs are sharing caches and you won't see the real downside of the spinlock. They don't really fall apart until you have several sockets.
25.
by rwem 7y ago
That's still unreasonably high, isn't it? Even a Go sync.Mutex, not exactly a hot-rod implementation, can be acquired and released in < 50ns on the garbage hardware I have before me.
26.
by rwem 7y ago
That’s what virtually all battle-hardened lock libraries do: spin for a bit (but not too tightly, using a pause in the loop) then fall back to waiter lists and futex.
27.
by rwem 7y ago
It doesn’t flush the entire cache (that would be a disaster) but it does shoot down the cache line containing the lock in all cores other than the one that acquired the lock. The real issue with spin locks is fairness. There’s no assurance
28.
by rwem 7y ago
It’s basically impossible. Unpowered hub motors drag a lot. Unpowered mid-drives are better because they have clutches or freewheels, but you’re still pedaling a fifty-pound bike. Some ebikes do have regeneration triggered by brake lever sw