Pages that are fast to render can be omitted from the parser cache
to preserve disk space and cache write operations.
The threshold is configurable per namespace, so the tradeoff can
be evaluated based on different access patterns. For example, pages
that are accessed rarely, like file description pages on commons,
may have a high threshold configured, while pages that are read
frequently, like wikipedia articles, may be configured to be always
cached, using a 0 threshold.
Filtering is based on a time profile recorded in the ParserOutput.
A generic mechanism for capturing the timing profile is implemented
in the ContentHandler base class. Subclasses may implement a more
rigorous capture mechanism.
Bug: T346765
Change-Id: I38a6f3ef064f98f3ad6a7c60856b0248a94fe9ac
e3fb964439