Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 696 posts.
Your code might be perfect and never fail, but unfortunately the outside world is less reliable. Sometimes, other people's programs crash or freeze. Networks go down; printers catch on fire . Your code needs to be prepared for this: every time you read from the network, attempt to acquire an inter-process lock, or…
Memory management is the heart of operating systems; it is crucial for both programming and system administration. In the next few posts I'll cover memory with an eye towards practical aspects, but wi
Unexpected performance deviations depending on how you spell zero.
I wrote this article for an online magazine called Scene Zine . Scene Zine caters to the Demo Scene, which is an digital art community dedicated to pushing the limits of computers through a mix of music, art, and computer programming. A particular category of demoscene productions, 4K intros, focus on the final…
This post is about an obscure corner of TCP network programming, a corner where almost everybody doesn’t quite get what is going on. I used to think I understood it, but found out last week that I didn’t.
The 1600 LoC patch allows userspace to pass the kernel the encryption keys for an established connection, making encryption happen transparently inside the kernel.
In many information systems, we work with arrays of integers. For example, maybe you need to keep track of which records in a database contain a given value. This sort of mapping can be expressed as an array of integers. These arrays can end up taking up a large fraction of your memory or disk … Continue reading…
In the last Jepsen analysis, we saw that RethinkDB 2.2.3 could encounter spectacular failure modes due to cluster reconfiguration during a partition. In this analysis, we’ll talk about Crate, and find out just how many versions a row’s version identifies.
Updated February 2, 2016: Once you learn about our team and who we are, come take a trip down memory lane with us! Yesterday morning, the Hosted UI team, responsible for VMware’s Workstation …
You might have read that Mozilla recently switched Windows builds to clang-cl . More recently, those Windows builds have seen both PGO (Profile-Guided Optimization) and LTO (Link-Time Optimization) enabled .
DISCLAIMER : The following are my own personal opinions and are not shared, sanctioned or endorsed by anybody in particular, especially my employer. Any criticisms expressed herein are of a general nature and are neither inspired by nor directed at any person, entity, or product in particular. Links to other online…
The latest version of the Intel manual has a couple of new instructions for non-volatile storage, like SSDs . What's that about?
Resurrecting an old tradition of this blog, let’s take a simple problem, go over a way too long list of alternative solutions, and evaluate their merits. Our simple problem is this: we want t…
This is a followup to my previous post, prefix sum on Vulkan. Last year, I got a fancy algorithm for this problem running well on one device. This time, I will dive into the question of how to make it work well across a wide range of devices. The short answer is, it can be made to work pretty portably on Vulkan and…
This blog post has been archived! SpacetimeDB has improved a lot since I initially published this technical review, and most of the technical details in it no longer apply.
In this article I describe the DEFLATE algorithm that GZIP implements and depends on. The DEFLATE algorithm uses a combination of LZ77, Huffman codes and run-length-encoding; this article describes each in detail by walking through an example and developing source code to implement the algorithm. My aim is to…
It's taken me much longer than I hoped, but I finally have a second version of my patches to build static executables tested and ready to go! This set of patches vastly improves upon the first by reducing the amount of compilation needed at the cost of sacrificing a little purity. Additionally I have created a system…
With Computex, there’s been a ton of news about Ice Lake (hereafter ICL) and the Sunny Cove core (SNC). Wikichip, Extremetech and Anandtech among many others have coverage (and there will be …
A little fun for the last day of 2012: how to crash a program via division? x86’s IDIV instruction traps not only on division by zero, but also on INT_MIN / -1 (signed integer overflow).
Unikernel Profiling: Flame Graphs from dom0. This post investigates performance profiling of Unikernels, and with a proof of concept shows that with a little work a lot of observability is possible.
In this post we'll discuss the second argument on why the epoll() is broken. The problem is best described in an LWN comment by Foom :
I occasionally do talks about curl. In these talks I often include a few slides that say something abut curl's coverage and presence on different platforms. Mostly to boast of course, but also to help explain to the audience how curl has manged to reach its ten billion installations. This is current incarnation of…
I have recently published a blog post that, as I had expected (actually, hoped for, as that would attract people to contribute to the “study”), generated quite some polemic on the Internet!
Backpressure is something nearly every software engineer will have to deal with at some point, and for some it’s a frequent problem. But…
At Twitter, a team had a unusual failure where corrupt data ended up in memcache. The root cause appears to have been a switch that was corrupting packets. Most packets were being dropped and the throughput was much lower than normal, but some were still making it through. The hypothesis is that occasionally the…
Perf is probably the most widely used general purpose performance debugging tool on Linux. There are multiple contenders for the #2 spot, and, like perf, they're sampling profilers. Sampling profilers are great. They tend to be easy-to-use and low-overhead compared to most alternatives. However, there are large…
This post is based on the talk of the same name I gave at the Arrrrcamp conference in Ghent, Belgium on October 2nd, 2014. You can find the slides here and the video recording here .
The behavior of the Windows scheduler changed significantly in Windows 10 2004 (aka, the April 2020 version of Windows), in a way that will break a few applications, and there appears to have been …
