Summary:
QDateTime::fromMSecSinceEpoch uses Qt::LocalTime by default. This involves an
expensive localtime conversion. So instead force things to use UTC, as there
is no need for timezone information when tracking durations.
This is especially noticeable on Bedrock Linux, which uses a Fuse mounted
/etc, which is slower than a plain /etc and causes quite some slowdown there.
See https://github.com/bedrocklinux/bedrocklinux-userland/issues/140 for
details.
Test Plan: The screenedge unit test still passes.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: zzag, anthonyfieroni, davidedmundson, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D27114
9b3d9e58a4