defer, deferlow and when to use it
hi there,
once again a very basic question: i'm quite new to deferral and not really understanding it yet :)
i have a m4l patch (but it guess it applies to general patching, too) with rather heavy visual feedback (sliders, moving and blinking stuff – all not *really* essential for the underlying functionality etc).
is it generally a good idea to add a defer (or deferlow?) before all of this?
or am i on a totally wrong page as for these objects ?
thanks :)
'defer' will reschedule events from any non-UI thread to the main/UI thread (AKA the low priority thread in some of our documentation). If the event is already in the main thread, it will just pass through.
'deferlow' will reschedule all events, from all threads, to the next 'tick' of the main thread. If the event is already in the main thread, it will also be rescheduled.
Painting is not controlled by the objects themselves, the object can tell Max that it wants to be repainted, but the actual drawing will always happen at the appropriate time (in the main thread). So there's no need to reschedule your events for that. But messages which cause a lot of (non-time-critical) calculation, or could block their thread for some other reason (opening a dialog box, for instance), should generally be rescheduled to avoid causing timing problems or clicks in the timer or audio threads.
FYI, most objects which perform file operations already do an internal deferral anyway, and the M4L live.api objects also reschedule incoming messages, since the Live API only works in the main thread. Jitter objects typically do the right thing, as well.
In brief, if you're not experiencing timing or audio outages, you probably don't need deferral for your messages. Here's an article from Joshua which is still relevant, covering this topic in more detail: https://cycling74.com/articles/event-priority-in-max-scheduler-vs-queue/
Jeremy
thanks so much for the layman's explanation, jeremy. this is of great help for me and i'll be doing some reading up.
in my patch, i'm facing a really strange phenomenon: whenever i click the on the background of the patch running in live (albeit there is actually nothing there?!), all visual elements get stuck for ~400ms, then continue to run / blink / etc.. – if however i place a blank panel on the background, this doesn't happen. do you have a general idea why this could be? or do you suppose / can it even be something patch-specific?
thanks again
ps: i am the synchonization of my patch (it's a sequencer) from plugsync~.. may this be a bug in this object or something?