match: remove unnecessary optimization where visitdir() returns 'all' Match's visitdir() was prematurely optimized to return 'all' in some cases, so that the caller would not have to call it for directories within the current directory. This change makes the visitdir system less flexible for future changes, such as making visitdir consider the match's include and exclude patterns. As a demonstration of this optimization not actually improving performance, I ran 'hg files -r . media' on the Mozilla repository, stored as treemanifest revlogs. With best of ten tries, the command took 1.07s both with and without the optimization, even though the optimization reduced the calls from visitdir() from 987 to 51.

dispatch: add support for python-flamegraph[0] profiling This gives us nicer svg flame graphs for output, which can make understanding some types of performance problems significantly easier. 0: https://github.com/evanhempel/python-flamegraph/

extensions: document that `testedwith = 'internal'` is special Extension authors (notably at companies using hg) have been cargo-culting the `testedwith = 'internal'` bit from hg's own extensions, which then defeats our "file bugs over here" logic in dispatch. Let's be more aggressive about trying to give extension authors a hint about what testedwith should say.

treemanifest: cache directory logs and manifests Since manifests instances are cached on the manifest log instance, we can cache directory manifests by caching the directory manifest logs. The directory manifest log cache is a plain dict, so it never expires; we assume that we can keep all the directories in memory. The cache is kept on the root manifestlog, so access to directory manifest logs now has to go through the root manifest log. The caching will soon not be only an optimization. When we start lazily loading directory manifests, we need to make sure we don't create multiple instances of the log objects. The caching takes care of that problem.