Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In interactive applications it's important to be able to shut down pipelines which are no longer needed as quickly as possible.
Right now, shutdown can be very slow. For example, vips_subsample() on a large image can maybe take 1 or 2 seconds per tile, so it can take 1 or 2 seconds between the start of shutdown and the exit of any threads. If the user is updating the operation graph faster than that, pipelines will start to back up and the system will lag badly.
This PR adds vips__worker_exit(), a fast test-for-shutdown that operations can call in their generate function.
It adds vips__worker_exit() to vips_subsample() and successfully stops pipelines lagging for nip4 previews. Some other slow operations should probably have calls added too (shrink, reduce, conv, perhaps others), but they can be added later as required.