https://weichengyi.com/ Notes on systems programming. en Sat, 12 Sep 2026 06:18:32 +0000 https://weichengyi.com/posts/monomorphisation-is-why-your-binary-is-big.html https://weichengyi.com/posts/monomorphisation-is-why-your-binary-is-big.html Sun, 05 Jul 2026 00:00:00 +0000 Zero-cost at runtime is not zero-cost at build time, and the bill arrives in bytes. https://weichengyi.com/posts/what-pin-actually-guarantees.html https://weichengyi.com/posts/what-pin-actually-guarantees.html Mon, 27 Apr 2026 00:00:00 +0000 Less than people assume, and precisely enough to make self-referential futures sound. https://weichengyi.com/posts/the-question-mark-is-not-exception-handling.html https://weichengyi.com/posts/the-question-mark-is-not-exception-handling.html Wed, 11 Feb 2026 00:00:00 +0000 It looks like a throw. It is a return. https://weichengyi.com/posts/who-ends-up-in-time-wait.html https://weichengyi.com/posts/who-ends-up-in-time-wait.html Wed, 03 Dec 2025 00:00:00 +0000 Not whoever you think. It is decided by who closes first, and that decides whose problem it is. https://weichengyi.com/posts/false-sharing-costs-more-than-you-think.html https://weichengyi.com/posts/false-sharing-costs-more-than-you-think.html Tue, 14 Oct 2025 00:00:00 +0000 Two counters that have nothing to do with each other, sharing 64 bytes, can cost you an order of magnitude. https://weichengyi.com/posts/edge-triggered-is-a-contract.html https://weichengyi.com/posts/edge-triggered-is-a-contract.html Sat, 09 Aug 2025 00:00:00 +0000 EPOLLET does not make epoll faster by itself. It moves an obligation onto you. https://weichengyi.com/posts/slow-start-is-not-slow.html https://weichengyi.com/posts/slow-start-is-not-slow.html Sat, 21 Jun 2025 00:00:00 +0000 The name describes where it begins, not how fast it moves. https://weichengyi.com/posts/so-reuseaddr-is-not-so-reuseport.html https://weichengyi.com/posts/so-reuseaddr-is-not-so-reuseport.html Fri, 02 May 2025 00:00:00 +0000 Two socket options, one letter apart in conversation, solving completely different problems. https://weichengyi.com/posts/why-a-binary-says-glibc-2-34-not-found.html https://weichengyi.com/posts/why-a-binary-says-glibc-2-34-not-found.html Tue, 18 Mar 2025 00:00:00 +0000 The first time you copy a working binary to an older server and it refuses to start, the error looks like a broken build. It is not.