https://rigtorp.se/ Recent content on Erik Rigtorp Hugo -- gohugo.io en-us Sun, 06 Nov 2022 21:24:24 -0600 https://rigtorp.se/notes/dark-mode-svg/ Sun, 06 Nov 2022 21:23:20 -0600 https://rigtorp.se/notes/dark-mode-svg/ I recently added dark mode support to my website. While doing so I found a neat trick to make SVG images that changes colors depending on if dark mode is active or not. https://rigtorp.se/notes/skopt/ Sun, 06 Nov 2022 21:23:20 -0600 https://rigtorp.se/notes/skopt/ In this note I show how you can parallelize scikit-optimize (skopt) using Dask. https://rigtorp.se/ringbuffer/ Mon, 13 Dec 2021 00:00:00 +0000 https://rigtorp.se/ringbuffer/ In this article I will take a look at the classic concurrent ring buffer and how it can be optimized to increase throughput. https://rigtorp.se/notes/weechat/ Wed, 01 Dec 2021 23:45:30 +0100 https://rigtorp.se/notes/weechat/ This is a short guide how to setup WeeChat WebSocket relay protocol with TLS encryption. https://rigtorp.se/notes/perf/ Wed, 01 Dec 2021 23:37:52 +0100 https://rigtorp.se/notes/perf/ In this note I provide some useful examples on how to use perf. https://rigtorp.se/notes/rocm/ Sat, 07 Nov 2020 00:00:00 +0000 https://rigtorp.se/notes/rocm/ This is guide on how to install ROCm 3.9 on Fedora 33 using the official packages for RHEL8. https://rigtorp.se/notes/figures/ Tue, 20 Oct 2020 13:02:29 -0700 https://rigtorp.se/notes/figures/ A list of useful tools for creating figures and diagrams for technical documentation. https://rigtorp.se/notes/pgo/ Fri, 16 Oct 2020 21:23:29 -0700 https://rigtorp.se/notes/pgo/ Profile-guided optimization (PGO), also known as profile-directed feedback (PDF), and feedback-directed optimization (FDO) is a compiler optimization technique in computer programming that uses profiling to improve program runtime performance. https://rigtorp.se/hugepages/ Thu, 08 Oct 2020 00:00:00 +0000 https://rigtorp.se/hugepages/ In this article I will explain when and how to use huge pages. https://rigtorp.se/fuzzing-floating-point-code/ Mon, 21 Sep 2020 00:00:00 +0000 https://rigtorp.se/fuzzing-floating-point-code/ In this article I demonstrate how to fuzz test floating point code using libFuzzer. https://rigtorp.se/notes/clang-format/ Sat, 19 Sep 2020 23:02:42 -0700 https://rigtorp.se/notes/clang-format/ In this note I provide useful tips on how to use ClangFormat (somtimes called clang-format). https://rigtorp.se/generating-ostream-operator/ Fri, 18 Sep 2020 00:00:00 +0000 https://rigtorp.se/generating-ostream-operator/ In this article I describe how to automatically generate implementations for std::ostream &operator<< for enums and structs from C++ source code using LibClang. https://rigtorp.se/sockets/ Mon, 10 Aug 2020 00:00:00 +0000 https://rigtorp.se/sockets/ My notes on common gotchas and usage tips for usign the POSIX sockets API (also known as Berkeley sockets or BSD sockets). https://rigtorp.se/notes/hashing/ Tue, 04 Aug 2020 14:07:05 -0700 https://rigtorp.se/notes/hashing/ For user supplied data use SipHash to prevent hash flood attacks. https://rigtorp.se/iife/ Mon, 13 Jul 2020 00:00:00 +0000 https://rigtorp.se/iife/ The immediately invoked function expression (IIFE) is a concept that has been independently discovered multiple times and applicable to multiple programming languages. https://rigtorp.se/virtual-memory/ Thu, 09 Jul 2020 00:00:00 +0000 https://rigtorp.se/virtual-memory/ This is a short guide describing the latency implications of the virtual memory abstraction. https://rigtorp.se/notes/jellyfin/ Tue, 09 Jun 2020 22:54:14 -0700 https://rigtorp.se/notes/jellyfin/ Jellyfin Jellyfin is a open source media streaming solution that can be used to stream your own media library. https://rigtorp.se/notes/avx/ Tue, 09 Jun 2020 22:53:29 -0700 https://rigtorp.se/notes/avx/ AVX loads and stores are atomic See AVX loads and stores are atomic and https://stackoverflow. https://rigtorp.se/notes/dns/ Sun, 07 Jun 2020 13:55:14 -0700 https://rigtorp.se/notes/dns/ DNS Privacy and Security on Fedora This is a short guide how to setup DNS Privacy on Fedora Workstation. https://rigtorp.se/notes/hardening-ssh/ Sun, 07 Jun 2020 13:55:14 -0700 https://rigtorp.se/notes/hardening-ssh/ Hardening SSH against password brute-force attacks If your SSH server is publicly accessible over the internet it will be subjected to password brute-force attacks. https://rigtorp.se/notes/postfix/ Sun, 07 Jun 2020 13:55:14 -0700 https://rigtorp.se/notes/postfix/ Configure Postfix to use external SMTP server as relay This is a short guide how to setup Postfix to deliver mail using an external SMTP server as relay host. https://rigtorp.se/isatomic/ Sat, 06 Jun 2020 00:00:00 +0000 https://rigtorp.se/isatomic/ On the latest CPU microarchitectures (Skylake and Zen 2) AVX/AVX2 128b/256b aligned loads and stores are atomic even though Intel and AMD officially doesn’t guarantee this. https://rigtorp.se/spinlock/ Sat, 25 Apr 2020 00:00:00 +0000 https://rigtorp.se/spinlock/ I’ve seen a lot of poorly implemented spinlocks floating around the internet. https://rigtorp.se/low-latency-guide/ Wed, 25 Mar 2020 00:00:00 +0000 https://rigtorp.se/low-latency-guide/ This guide describes how to tune your AMD64/x86_64 hardware and Linux system for running real-time or low latency workloads. https://rigtorp.se/split-locks/ Thu, 16 Jan 2020 00:00:00 +0000 https://rigtorp.se/split-locks/ The x86-64 architecture allows unaligned memory access. It even allows for atomic operations on data split across two cache lines. https://rigtorp.se/cpp-best-practices/ Sun, 22 Sep 2019 00:00:00 +0000 https://rigtorp.se/cpp-best-practices/ Opinionated C++ one page best practices guide. Adapt according to your project’s requirements. https://rigtorp.se/2013/06/08/estimating-order-queue-position.html Sat, 08 Jun 2013 00:00:00 +0000 https://rigtorp.se/2013/06/08/estimating-order-queue-position.html When developing algorithmic trading strategies for FIFO markets it is beneficial to know our orders queue position in the order book. https://rigtorp.se/2012/11/22/feed-handler.html Thu, 22 Nov 2012 00:00:00 +0000 https://rigtorp.se/2012/11/22/feed-handler.html The feed handler is one of the most important component of any algorithmic trading system. https://rigtorp.se/2011/01/01/rolling-statistics-numpy.html Sat, 01 Jan 2011 00:00:00 +0000 https://rigtorp.se/2011/01/01/rolling-statistics-numpy.html When working with time series data with NumPy I often find myself needing to compute rolling or moving statistics such as mean and standard deviation. https://rigtorp.se/latency.html Fri, 20 Nov 2009 00:00:00 +0000 https://rigtorp.se/latency.html Introduction Latency is a tricky subject, sometimes it's not even clear what or how to measure it.