Ask HN: How can I learn about performance optimization?

> But knowing what needs to be optimized doesn't necessarily mean you know how to optimize it.

True, although not knowing what needs to be optimized guarantees that you don't know how to optimize it :).

> knowing more about how to actually write optimized code can help you make more informed decisions earlier on in the development process.

Totally agree though, despite poking a bit of fun.

This is something that I've been decently good at for many years. If I had to give someone new to it advice, it'd be:

- learn how to repeatably measure your system without introducing too much overhead. If you get this wrong, you're going to end up tricking yourself into believing you've made an improvement but instead got lucky/unlucky.

- once you've found the repeatably-measureable hotspots, the optimization approach is going to depend dramatically on the problem domain. Optimizing for database disk throughput is different than optimizing for http server response-latency is different than squeezing more polygons into a frame in a game.

The one very important thing to keep in mind though is that you're going to need to peel back the abstractions and understand what's happening under the hood. This applies to both parts. Maybe the way to measure what's happening in your network service is to use tcpdump to capture the raw packets and see that you're sending a bunch of small writes into a socket instead of a single big write (why is that a problem? :D). Or something like NVidia NSight can provide a ton of insight into what's happening on your CPUs and GPU frame-to-frame.

This quote has done more damage to software usability than any other idea of the last 60 years. It has lead us to a state where software is unbearably slow because nothing was worth optimizing. Just like it's easy to go broke with thousands of minor expenses, it's easy to create sluggish software that has no obvious bottleneck because the whole damn thing is slow.

I admire Daniel Lemire’s work on SIMD implementations. [Lemire]

[Lemire] https://lemire.me/en/#publications

I learn a lot by reading my compiler’s and profiler’s documentation.

For Rust, the Rust Performance Book by Nicholas Nethercote et al. [Nethercote] seems like a nice place to start after reading the Cargo and rustc books.

[Nethercote] https://nnethercote.github.io/perf-book/

Algorithms for Modern Hardware by Sergey Slotin [Slotin] is a dense and approachable overview.

[Slotin] https://en.algorithmica.org/hpc/

Quantitative understanding of the underlying implementations and computer architecture has been invaluable for me. Computer architecture: a quantitative approach by John L. Hennessy and David A. Patterson [H&P] and Computer organization and design: the hardware/software interface by Patterson and Hennessy [P&H ARM, P&H RISC] are two introductory books I like the best. There are three editions of the second book: the ARM, MIPS and RISC-V editions.

[H&P] https://www.google.com/books/edition/_/cM8mDwAAQBAJ

[P&H ARM] https://www.google.com/books/edition/_/jxHajgEACAAJ

[P&H RISC] https://www.google.com/books/edition/_/e8DvDwAAQBAJ

Compiler Explorer by Matt Godbolt [Godbolt] can help better understand what code a compiler generates under different circumstances.

[Godbolt] https://godbolt.org

The official CPU architecture manuals from CPU vendors are surprisingly readable and information-rich. I only read the fragments that I need or that I am interested in and move on. Here is the Intel’s one [Intel]. I use the Combined Volume Set, which is a huge PDF comprising all the ten volumes. It is easier to search in when it’s all in one file. I can open several copies on different pages to make navigation easier.

Intel also has a whole optimization reference manual [Intel] (scroll down, it’s all on the same page). The manual helps understand what exactly the CPU is doing.

[Intel] https://www.intel.com/content/www/us/en/developer/articles/t...

Personally, I believe in automated benchmarks that measure end-to-end what is actually important and notify you when a change impacts performance for the worse.

>hn.algia.com

Sorry, only noticed the typo now:

Should be hn.algolia.com

Read some of the performance-related work here: https://acl.inf.ethz.ch/publications/