jlokier

56 ms·

511.
by jlokier 4y ago
I agree that linear reads and writes are not relevant these days in most settings. I've worked on my own DB engine that uses a structure similar to LSM (but it's not an LSM tree), where the highest possible performance (millions o
512.
by jlokier 4y ago
> However, I think you’re making a mistake on a core part of your argument: No, that part has been misunderstood so I guess I didn't write it clearly enough. I'm not saying the filesystem defragments, or does any particular eff
513.
by jlokier 4y ago
> you really can't beat a LSM design for write-heavy workload Depending on the write pattern, you actually can, because standard LSM-trees write the same data repeatedly, into each layer, and again if recompacting a layer. They m
514.
by jlokier 4y ago
One thing about LSM trees that are implemented with large numbers of large files in a filesystem, such as RocksDB, is that they defer to the filesystem to deal with fragmentation and block lookup isues. That's not actually free. LSM t
515.
by jlokier 4y ago
Your protons are also oriented by the Earth's magnetic field, and the magnets in your phone speakers. Larmor precession (the effect) occurs in low fields just as in high fields. The energy state differences from Earth's field ar
516.
by jlokier 4y ago
I was going to say I expect much of the gain to come from "pragma synchronous=normal", which tells your MBP M1 to not bother committing the data to SSD robustly before telling the application that the insert is committed. From Sq
517.
by jlokier 4y ago
I had a similar result with storage I/O to NVMe SSDs. io_uring was slightly slower than my optimised Linux thread pool at 4k random-access I/O at about 2.5M IOPS in my benchmarks, and this despite the syscall overhead in the thre
518.
by jlokier 4y ago
Good point. That might be the way to go. Thanks for the suggestion. I hadn't thought of it, as older USB drives (ie. my experience, 2013 MBP) are much slower for large data than the internal storage, some of my work is storage I/
519.
by jlokier 4y ago
Thanks!
520.
by jlokier 4y ago
Later versions of macOS can be installed on older hardware than is officially supported by Apple, by using OpenCore Legacy Patcher: https://dortania.github.io/OpenCore-Legacy-Patcher/
521.
by jlokier 4y ago
Later versions of macOS can be installed on older hardware than is officially supported by Apple, by using OpenCore Legacy Patcher: https://dortania.github.io/OpenCore-Legacy-Patcher/
522.
by jlokier 4y ago
> Apple's SSDs have built-in protection against data-loss from power loss which is usually an enterprise SSD feature. It's a bit arguable. On Macos the well-known operation 'fsync' which exists for the sole purpose
523.
by jlokier 4y ago
That's true for the memory (RAM), but not the storage (SSD). Socketed SSDs are just as fast and almost as light as soldered, and there is no good technical reason why they shouldn't be upgradable for a long time. I'm in the
524.
by jlokier 4y ago
Fortunately a large mirror doesn't have to be a continuous surface, and it doesn't need all of that area either. A constellation of optically linked telescopes each with small mirrors would be able to image the same exoplanet. Con
525.
by jlokier 4y ago
Thanks for this link. Unfortunately it's how I found my ISP, Three in the UK, now blocks archive.org because of "adult content". (In Firefox the block makes it look like a server configuration error on archive.org itself, bu
526.
by jlokier 4y ago
Same here. I'd happily pay the monthly rent if it's worth it, but not if I find after a few hours testing that it's slower for my purposes than 2 AX101s (2 because of the price ration and SSD sizes). I might try it on Scalew
527.
by jlokier 4y ago
No. See https://news.ycombinator.com/item?id=26058061 about the M1. If ECC were added between M1 and M2, Apple would almost certainly have announced it as a feature.
528.
by jlokier 4y ago
Glibc's mangles some pointer registers in setjmp(). It XORs a per-process value with the stack pointer, frame pointer and instruction pointer stored in the jmp_buf, on all (or nearly all) architectures. Although losing the stack and i
529.
by jlokier 4y ago
Your NVMe SSD gets 1 million IOPs with overlapping requests. That means each new request issued does not wait for the previous one to finish. There's a queue depth, and keeping it full enough is needed to reach 1 million IOPS through
530.
by jlokier 4y ago
Some people say they don't have a mind voice, and grow up thinking nobody does. Other people, with a mind voice, grow up thinking everyone does. I've been in the room when people compared notes as adults, and were mind-blown to
531.
by jlokier 4y ago
Apple themselves offer a battery replacement service for a fee, and it seems to be a reasonable fixed price (where I live). You might still be able to get them to upgrade that Macbook's battery. Don't use an Apple Reseller for th
532.
by jlokier 4y ago
> Fewer context switches among user space / kernel syscalls Note that each page fault to read an mmaped page is also a context switch from user space into the kernel. The kernel entry/exit paths for syscalls and page faults h
533.
by jlokier 4y ago
You misread the sentence. Janet supports full parallel execution on multiple CPU cores using native operating system threads, while using clean and fast single-threaded data structures by default on each thread .
534.
by jlokier 4y ago
> The whole point of io_uring is to drastically decrease the number of sys calls, creating channels where more requests can be filed with lower than traditional cost of a readFile syscall for example, and where completion can also be lo
535.
by jlokier 4y ago
About signed commits, but off topic for the article: Many signed commits ("Verified" in green) on GitHub are signed with GitHub's own private key¹, not the committer's key. There's a good technical reason, but many
536.
by jlokier 4y ago
The Linux kernel since 2.6.25 provides CPU time limits on real-time priority so that runaway real-time tasks don't prevent other interactive processes from having some CPU time. So you can still interact with the system. "man 7 sc
537.
by jlokier 4y ago
That waa me. My 6502 "IDE" was a BBC Micro, with it's excellent BBC BASIC ROM that had inline 6502 assembler built-in to the BASIC language. It was so good and accessible, and documented in the Advanced User Guide, that after
538.
by jlokier 4y ago
I agree, though my last mile latency to the nearest POP is about 85ms. Still a bit on the high side for action games compared with playing locally.
539.
by jlokier 4y ago
Hmm. I do about 200 searches a day on Google, so that would be $92/month. I'd pay for the service if all search engines charged that much, because search is so useful. But in that world, I'd be more cautious about searching
540.
by jlokier 4y ago
That gov.uk calculator is incorrect, which is unusual for gov.uk. It hasn't reduced the tax-free allowance to zero as it should for £150k. Most other online tax calculators do, so they show a lower take home amount. The 60% that is dis

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