Optimizing ccache using per-package caches

ccache can be of great assistance to Gentoo developers and users who frequently end up rebuilding similar versions of packages. By providing a caching compiler frontend, it can speed up builds by removing the need to build files that have not changed again. However, it uses a single common cache directory by default which can be suboptimal even if you are explicitly enabling ccache only for a subset of packages needing that.

The likeliness of cross-package ccache hits is pretty low — majority of the hits occurs within a single package. If you use a single cache directory for all affected packages, it grows pretty quick. Besides a possible performance hit from having a lot of files in every directory, this means that packages built later can shift earlier packages out of the cache, resulting in meaninglessly lost cache hits. A simple way to avoid both of the problems is to use separate ccache directories.

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GLEP 73 check results explained

The pkgcheck instance run for the Repo mirror&CI project has finished gaining a full support for GLEP 73 REQUIRED_USE validation and verification today. As a result, it can report 5 new issues defined by that GLEP. In this article, I’d like to shortly summarize them and explain how to interpret and solve the reports.

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