871
Async hazard: MMAP is blocking IO
Memory-mapping a file is convenient, but it's a hazard when used with async/await concurrent code: it means a "simple" memory index does blocking IO.
New
The latest blog posts to take off on Hacker News. 4,387 posts.
872
Mimalloc Cigarette: Losing one week of my life catching a memory leak (Rust)
How do you solve a memory heisenbug?
873
Making database systems usable
C. J. Date's Sigmod 1983 keynote, "Database Usability", was prescient. Usability is the most important thing to the customers. They care les...
874
The LMAX Architecture (2011)
LMAX is a retail financial trading system that can handle that can 6 million orders per second on a single JVM thread. The business logic runs in-memory surrounded by disruptors using event sourcing.
875
Re-fixing Servo's event-loop
A follow-up on a previous story, in which we identify another problem, and perhaps confirm a theory through a theorem.
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Zen5's AVX512 Teardown and More
This article was supposed to be published all at once on July 30'th. But because of the staggered launch delay into August 8 and 15, some sections of this article were redacted until August 14th.
878
Building rqlite 9.0: Cutting disk usage by half
rqlite is a lightweight, open-source, distributed relational database written in Go. It is built on the Raft consensus protocol and uses SQLite as its storage engine. Development of 9.0 has begun and aims to reduce disk usage by approximately 50%. This goal will be achieved through a high-level design overhaul…
879
Debugging a rustc segfault on Illumos
Using `mdb` and `pmap` to find the cause of a crash.
880
C++'s `noexcept` can sometimes help or hurt performance
Over the course of working on PSRayTracing (PSRT), I've been trying to find all sorts of tricks and techniques to squeeze out more performance from this C++ project. Most of it tends to be alternative algorithms, code rewriting, and adjusting data structures. I thought sprinkling the final keyword like an all purpose…
881
How Postgres stores data on disk – this one's a page turner
A high-level overview of how PostgreSQL stores data on disk, covering segments, pages and more.
882
Revisiting Linux CPU Scheduling
Disclaimer: This is to the best of my knowledge. It's a complicated topic, there are tons of options, and this only covers a tiny fraction of this topic anyway. If you spot mistakes, please tell me.
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Rustgo: Calling Rust from Go with near-zero overhead (2017)
Go has good support for calling into assembly, and a lot of the fast cryptographic code in the stdlib is carefully optimized assembly, bringing speedups of over 20 times.
885
`find` + `mkdir` is Turing complete
We show that a system that has only GNU's find and mkdir commands is Turing-complete.
886
Building static binaries with Go on Linux
One of Go's advantages is being able to produce statically-linked binaries [1] . This doesn't mean that Go always produces such binaries by default, however; in some scenarios it requires extra work to make this happen. Specifics here are OS-dependent; here we focus on Unix systems.
887
Troubleshooting: Terminal Lag
I think I should blog more about random troubleshooting sessions, if nothing else it will remind me what steps I took when it inevitably happens again!
888
tolower() with AVX-512
A couple of years ago I wrote about tolower() in bulk at speed using SWAR tricks . A couple of days ago I was interested by Olivier Giniaux’s article about unsafe read beyond of death , an optimization for handling small strings with SIMD instructions, for a fast hash function written in Rust.
889
How simultaneous multithreading works under the hood
Learn the microarchitecture-level details of the processor that enable to execute two threads at the same time on a CPU core
890
Plan 9 is a uniquely complete operating system
A large contributor to the "feel" of an Operating System comes from the software it chooses to include by default. There are entire linux distributions that differentiate themselves just based on the default configured software. There is room for so many options of base software because there are in general many…
891
Lessons from Ancient File Systems
In my previous post , I mentioned that I found a number of oddities when digging through the details of various Atari 8-bit file systems. I...
892
Learning about PCI-e: Driver and DMA
Creating a simple driver for a simple PCI-e device (in QEMU)
893
Linux Network Performance Ultimate Guide
https://blog.packagecloud.io/illustrated-guide-monitoring-tuning-linux-networking-stack-receiving-data/
894
Scaling One Million Checkboxes to 650M checks
How I scaled One Million Checkboxes to handle half a million users
895
Bcachefs, an Introduction/Exploration
Introduction & background information NOTE: This content is from an internal talk I gave, thus the reason it may read like a presentation So what is …
896
How to build highly-debuggable C++ binaries
code { white-space : pre-wrap !important; } This article is tightly scoped to cover one topic with specific, actionable advice: How to configure...
897
Let's consign CAP to the cabinet of curiosities
Brewer’s CAP theorem, and Gilbert and Lynch’s formalization of it , is the first introduction to hard trade-offs for many distributed systems engineers. Going by the vast amounts of ink and bile spent on the topic, it is not unreasonable for new folks to conclude that it’s an important, foundational, idea.
898
Hiding Linux Processes with Bind Mounts
Lately I’ve been thinking about Stephan Berger’s recent blog post on hiding Linux processes with bind mounts. Bottom line here is that if you have an evil process you want to hide, use …
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"Doors" in Solaris: Lightweight RPC Using File Descriptors (1996)
A door is a "file" descriptor used to describe a procedure in a process and optionally some additional state associated with the procedure. Doors were initially designed as Spring object descriptors used to encapsulate the state and capabilities of C++ objects. A process which obtains a door is free to pass it, along…
900
Counting bytes faster than you'd think possible
“Summing ASCII Encoded Integers on Haswell at the Speed of memcpy” turned out more popular than I expected, which inspired me to take on another challenge on HighLoad: Counting uint8s . I’m currently only #13 on the leaderboard, ~7% behind #1, but I have already learned some interesting things. In this post I’ll…