Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 1,232 posts.
Here's the graph of a toy benchmark 1 of page-aligned vs. mis-aligned accesses; it shows a ratio of performance between the two at different working set sizes. If this benchmark seems contrived, it actually comes from a real world example of the disastrous performance implications of using nice power of 2 alignment…
Disclaimer: I used to work for Materialize which is one of the systems being compared in this post.
With the recent announcement of a commercial game shipping using Emscripten and asm.js , I thought it’d be a good time to explain how asm.js is executed in Firefox and some of the load-time optimizations we’ve made since the initial landing of OdinMonkey in March. (OdinMonkey is an optimization module inside Mozilla’s…
In this article I will take a look at the classic concurrent ring buffer and how it can be optimized to increase throughput.
Regular expressions – commonly known as RegExps – are a powerful and heavily used tool for manipulating strings in JavaScript. This post describes how we updated the RegExp engine in ...
Tim Kadlec writes about performance, product management, and the web.
About a year ago the PostgreSQL community discovered that fsync (on Linux and some BSD systems) may not work the way we always thought it is, with possibly disastrous consequences for data durability/consistency (which is something the PostgreSQL community really values).
In the process of writing a short introduction to RISC-V, we compared RISC-V vector code to SIMD. We were struck by the insidiousness of the SIMD instruction extensions of ARM, MIPS, and x86. We de…
As a rule, "sophisticated" progrmming is pretty boring - optimizing the unnecessary to speed up the uninteresting. Here, however, is an incredibly sophisticated package intended for fun and games. The more you know about software, the more astounded you will become as you read this.
Today we’re launching Amazon Time Sync Service, a time synchronization service delivered over Network Time Protocol (NTP) which uses a fleet of redundant satellite-connected and atomic clocks in each region to deliver a highly accurate reference clock. This service is provided at no additional charge and is…
I wanted to know how a modern C compiler like clang would process the following C code: #include <stdint.h> int count(uint64_t x) { int v = 0; while(x != 0) { x &= x - 1; v++; } return v; } Can you guess? popcntq %rdi, %rax That is right. A fairly sophisticated C function, … Continue reading The surprising cleverness…
Ah, C. The best lingua franca we have… because we have no other lingua francas. Linguae franca. Surgeons general? C is fairly old — 44 years, now! — and comes from a time when there were possibly more architectures than programming languages. It works well for what it is, and what it is is a relatively simple layer of…
In a recent blog post we explained how to tweak a simple UDP application to maximize throughput. This time we are going to optimize our UDP application for latency. Fighting with latency is a great excuse to discuss modern features of multiqueue NICs.
asm.js is an easy-to-optimize subset of JavaScript. It runs in all browsers without plugins, and is a good target for porting C/C++ codebases such as game engines - which have ...
"JVM Anatomy Quarks" is the on-going mini-post series, where every post is describing some elementary piece of knowledge about JVM. The name underlines the fact that the single post cannot be taken in isolation, and most pieces described here are going to readily interact with each other.
Quick edit: While I work on a proper update, I'll note here that several posters on reddit and hackernews have pointed out ways to bring the total size of the program down to 105 bytes while still printing the full "Hello, world!" Much credit goes to Josh Triplett , who produced the 105-byte version which you can find…
One of the big features for Go 1.1 is the new scheduler, contributed by Dmitry Vyukov. The new scheduler has given a dramatic increase in performance for parallel Go programs and with nothing better to do, I figured I'd write something about it.
This is a collection of information on severe ( SEV-0 or SEV-1 , the most severe incident classifications) incidents at Twitter that were at least partially attributed to cache from the time Twitter started using its current incident tracking JIRA (2012) to date (2022), with one bonus incident from before 2012. Not…
I wrote this document after receiving large amounts of email from people who would like to write an emulator of one or another computer but do not know where to start. Any opinions and advices contained in the following text are mine alone and should not be taken for an absolute truth. The document mainly covers…
Learn how the engineering team at Asana rewrote the Asana app to improve app performance and speed from an in-depth, technical perspective.
Your CPU has a 32-bit addition instruction that computes the sum of two 32-bit integers x and y, producing a 32-bit result. (The 33rd bit of the sum, the "carry bit", is usually thrown away.)
This is one of these things that look very obvious to me, to the point where it seems not worth discussing. However, I've heard the idea that "hardware magically makes things cheap" from several PhDs over the years. So apparently, if you aren't into hardware, it's not obvious at all.
This is the first post in a series about JIT compilers. The plan is to take a simple input language and develop some interpreters and JITs for it, in roughtly increasing degree of complexity. It's my hope that by the end of the series readers will have a good understanding of what it takes to develop a JIT compiler…
Our customers reasonably expect to be able to spend on their card, make bank transfers and pay their bills 24 hours a day, 365 days a year. Their lives don’t have downtime for maintenance so nor should we. We dedicate a lot of our engineering effort to minimise the risk of downtime during technical migrations and…
