[yvdriess]

Assuming that once determined at the start of the frame (e.g. camera position changes after user input handling), the transform matrices are not written to. They can then be freely shared across multiple cores without causing problems with coherency. The cache lines associated with the transform will be set to 'Shared' across all cores. Cache coherency will start to bite you in the ass in this situation if you start mutating the transforms while other threads are reading it, causing cache invalidations and pipeline flushes across all caches owning those lines.

In short, write a transform once and treat it as immutable. Do not reuse the Transform allocation for a good while for subsequent frames to ensure that its cache lines are no longer in cache. If you do need to reuse right away, you can force invalidate cache lines by addresses, so that the single-writer in the next step is the single (O)wner and no other caches need to invalidate anything.

[dakom]

Thanks - I'll have to do a bit more learning to really understand this, e.g. how mutability relates to cache lines and what "Shared" means in that context, but this gives me some good practical direction and insight to take it further :)