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Systems & Performance

The most popular blog posts about systems & performance on Hacker News. 287 posts.

2019
249

Bits on the Wire

Exactly 100% of everything on the Internet involves exchanging messages which represent items of interest to humans. These items can be classified into three baskets: One for “media” (images, sound, video), one for text (HTML, PDF, XML), and one for “objects” (chat messages, payments, love poems, order statuses). This…

253

Mispredicted branches can multiply your running times

Modern processors are superscalar, meaning that they can execute many instructions at once. For example, some processors can retire four or six instructions per cycle. Furthermore, many of these processors can initiate instructions out-of-order: they can start working on instructions that appear much later in the…

254

A fast alternative to the modulo reduction (2016)

Suppose you want to pick an integer at random in a set of N elements. Your computer has functions to generate random 32-bit integers, how do you transform such numbers into indexes no larger than N? Suppose you have a hash table with a capacity N. Again, you need to transform your hash values (typically 32-bit ……

261

Rethinking Files

In Unix, everything is a file. This is often viewed as a positive, but it's often a poor abstraction for many things. This discussion goes into some of the issues.

265

Instructions per cycle: AMD Zen 2 versus Intel

The performance of a processor is determined by several factors. For example, processors with a higher frequency tend to do more work per unit of time. Physics makes it difficult to produce processors that have higher frequency. Modern processors can execute many instructions per cycle. Thus a 3.4GHz processor has 3.4…

270

Cache tables

Hash tables are the most popular probabilistic data structure, by quite a margin. You compute some hash code then compute an array index from that hash code. If you’re using open addressing-c…