[plasma-framework] src/plasma: Look up dataengines in kf5/plasma/dataengines

[Aaron J. Seigo]

On Thursday, September 26, 2013 04:21:21 Sebastian Kügler wrote:
> You can find numbers of the SSD runs in my email "Plugin locator performance
> ballpark" to kde-frameworks-devel from September, 5. I haven't cleaned up
> my measurements on rotating metal.

oh wow, that is not encouraging. :/ i’m suddenly less enthused by this idea.

> Bottom line, if we're still not happy with the performance, we might need an
> on-disk cache in KPluginTrader, but the complexity of keeping that up to
> date with a system as flexible, dynamic and component-driven as Plasma, is
> something, say, "worth avoiding".

problem is that 100-300ms on a high end machine is not acceptable. 

given that we load plugins at various times during execution based on user 
interaction, this will not just impact on startup, but during runtime.

 without a cache we’d end up having to do something truly fun like put the 
lookups in a thread, keeping an in-memory cache ... not something i expect we 
can ask of every application developer, either. basically what dfaure said in 
the kf5-devel thread.

he also noted that it would be possible to use a cache that is updated when 
the item gets put on disk. e.g. as part of “make install”. that would be 
rather fantastic and probably resolve the issue entirely.

-- 
Aaron J. Seigo