Agner's CPU blog

Intel is producing C++ and Fortran compilers as well as several highly optimized function libraries for a variety of purposes. Software programmers who are using Intel's compilers and function libraries are not always aware that software produced with these tools may run slower than necessary when i...

I have written a series of five manuals describing everything you need to know about optimizing code for x86 and x86-64 family microprocessors, including optimization advice for C++ and assembly language, details about the microarchitecture and instruction timings of Intel, AMD and VIA processors, a...

The C++ Vector Class Library (VCL) is a tool that makes it easy to do multiple calculations simultaneously. Modern microprocessors have vector registers that allow you to do multiple operations in a single instruction. This principle is called SIMD (Single Instruction Multiple Data). The vector regi...

Forwardcom is a research project aiming at finding out what an ideal computer system would look like. Current microprocessors are bound by the legacy of old systems that were developed when priorities and technical limitations were very different from today. Learning from past mistakes and a long hi...

This blog is used for news and findings from my research on CPU microarchitecture and software optimization. Relevant comments of general interest are welcome. Less relevant comments may be moderated or deleted. Old messages and discussions from 2019 and earlier can be seen at an older version of th...