Quote:
Originally Posted by ultim
r2069 is out, and this build should be fun  I encourage you all to take a look at it, as it brings some serious enhancements to MT, and then some. Let's see...
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- The behavior of MT_SERIALIZED (mode 3) changed. While the earlier implementation caused all filters that are called from the serialized filter to be also serialized, now it only serializes the one and only filter that it is specified for. This has a couple of important consequences:
-- If you have a mode 3 filter towards the end of your script, the speed penalty is much-much less, since earlier basically your whole script went into mode 3, whereas now other filters can still execute in parallel. The placement of mode 3 filters in your script just got un-critical!
-- This also means it is now a really bad idea to have a big lock/mutex inside your GetFrame() instead of marking it as mode 3, because your plugin will exhibit the old behavior and you won't be able to benefit from the potential improvements at all.
-- There is also a downside: The new mode 3 theoretically does not provide the same amount of MT-protection as the old one. However, I'm not sure it matters to many plugins at all. If it does, the old mode will be re-introduced as mode 4. So keep me up-to-date!
[...]
Edit: Despite my obvious enthusiasm, this build is still a test build. Please treat it as such.
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I encountered this downside.
In MT mode MT_SERIALIZED filters are really getting parallel request for the same instance, that means that their GetFrame is called in a reentrant way, just if they were MT_NICE_FILTER.
That means that the internal working buffers allocated in filter's constructor are used parallel, which is not good at all.
When you encounter strange behaviour for a filter that specify itself as MT_SERIALIZABLE (such as my FFT3DFilter version does), then try a forced mode selection for it.
SetFilterMTMode("FFT3DFilter",MT_MULTI_INSTANCE,force=true)
Or if no autoregistering happens, just specify MT_MULTI_INSTANCE and look if it makes your process any better.