BTW the compare was buggy (didn't compare against song2). This was OK though, as
we stable sort songs, and they are always ordered as far as I know (I remember
adding this sort just in case they will not be sent ordered on day).
Each time the song is changed, the podcast backend checks whether the
new song is a podcast and, if so, mark it as listened to. This requires
1-2 db queries, so do it off the main thread.
Time to change song before: 300 ms
after: 50 ms usually, 80 ms sometimes
When starting clementine, each playlist is loaded in turn.
When loading a playlist, the new tab order is committed to the db,
but we don't need to do that here because we know that once all the
playlists are loaded the tab order will be the same as it was initially.
This speeds startup substantially.
kstartperf:
Before: 3.5s
After: 1.5s
The playlist fetching uses QtConcurrent to make the playlist on a
different thread (possibly concurrently for each item).
However, profiling reveals that the slow operation is fetching
the rows from the SQLite database, making this redundant.
Instead move the whole playlist loading, including the database access,
into a single function, and call that function in a different thread via
QtConcurrent::run.
This has the side effect of moving all the concurrent stuff from
PlaylistBackend into the callers.
kstartperf measures:
Before: 7.5s cold
3.6 s warm
After: ~4.0 s cold
3.5 s warm
Shouldn't change anything in practice, but better to have items correctly inserted as Internet items FWIW. And will avoid other "custom context menu not working" issues if one day we implement one for
these services.
A bit more information:
Normal transcoding worked fine, the transcoder object was in the main thread. In the network remote, a new transcoder object is created which runs in the network remote thread. When a song was transcoded there, the UI became unresponsive.
Removing the async bus callback solved the problem, exactly the g_source_remove() method caused it. Since the bus callback returned FALSE (GST_BUS_DROP), the watch was already removed. (See http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstBus.html#gst-bus-add-watch)
Krzysztof Sobiecki
John Maguire
Arnaud Bienner
Simeon Bird
Clementine Buildbot
Mark Furneaux
Andreas
Chocobozzz
Juan Luis Boya García