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Systems & Performance

The most popular blog posts about systems & performance on Hacker News. 6,943 posts.

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5461

Tracking down a Zsh history data loss bug

For many years, I sometimes discovered that commands I was sure I had run were no longer present in my Z shell history file (~/.zsh_history). In this article, I will show you how I tracked down the bug. Spoiler: ultimately, patching Zsh to make it crash loudly and analyzing the crash’s core dump was the winning…

5465

Demodulation of the LTE uplink

I have been playing with some LTE recordings to brush up my knowledge, since it isn’t a protocol I’m very familiar with. I’m specially interested in understanding the structure and properties of all the pilot signals. Textbooks and documentation are great, but nothing beats getting your hands dirty with some IQ…

5466

Debugging a Live Saturn V

We all have stories, as engineers, of fixing some crazy thing at the last minute right before the demo goes up. We have all encountered situations where we needed to fix something that was our fault and we needed to fix it now.

5467

Can LLMs model real-world systems in TLA+?

Editors’ note: AI has been actively pushing the frontier of applied formal methods for computing systems. In this article, the Specula team wrote about their experience of evaluating LLMs on modeling system code, the basic capability for agentic model checking, using TLA+, a specification language f

5468

Batch computing and the coming age of AI systems

There’s a lot of excitement right now about human-in-the-loop systems supercharged by foundation models including chat assistants ( ChatGPT ), word processing ( Microsoft Office ), graphic design ( Stable Diffusion ), and code editing ( Copilot ). However, these systems only begin to scratch the surface of the role…

5470

Amazon Aurora PostgreSQL Serverless

The database is usually the most critical part of a software architecture and managing databases, especially relational ones, has never been easy. For this reason, we created Amazon Aurora Serverless, an auto-scaling version of Amazon Aurora that automatically starts up, shuts down and scales up or down based on your…

5471

Life of an instruction in LLVM

LLVM is a complex piece of software. There are several paths one may take on the quest of understanding how it works, none of which is simple. I recently had to dig in some areas of LLVM I was not previously familiar with, and this article is one of the outcomes of this quest.

5473

Waiting for many things at once with io_uring

When doing systems programming we often need to wait for something to happen. Common examples might be waiting for some data to come through a socket or waiting on a lock. We also often want to wait on any of several conditions to become true. A web server might be handling many sockets at once, waiting for any number…

5483

Running 9front on an emulated SGI Indy via MAME

I recently found that MAME supports running the SGI Indy while looking for ways to test some modifications I was making to the mips code in 9front. After a fair bit of elbow grease cinap and I (but mostly cinap) were able to get the old 9front indy kernel booting and running within mame. I thought I might as well…

5486

How Do I Profile eBPF Code?

If we are running any eBPF workload or writing eBPF code, we want to measure its performance impact, and in this post we will demonstrate an example of how to do it. In this example, our goal is to measure the performance of file open operations, one of the most critical functions in the OS. Our code used file open…

5489

Why Linux is not ready for the desktop, the final edition

The previous iteration of this article was too technical, too long, and contained a lot of controversial points, so I've been thinking for a long time about rewriting it completely, making it accessible to the non-technical folks, and exposing the deeper core issues that still make Linux a questionable match for the…