Fix unnecessary serialisation of PassManager
in serial contexts (backport #12410)
#12413
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Outdated suggestions cannot be applied.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.
Summary
This exposes the interal decision in
parallel_map
of whether to actually run in serial or not. If not, there's no need forPassManager
to side-car itsdill
serialisation onto the side of the IPC (we usedill
because we need to pickle lambdas), which can be an unfortunately huge cost for certain IBM pulse-enabled backends.Details and comments
@sbrandhsn: as the release manager for 1.1.0, it's up to you whether you want to accept this PR in this form for 1.1.0, or defer to 1.1.1 (you can tag the milestone appropriately). I could also suppress exporting
should_run_in_parallel
into the public namespace if you're not on board with a new public feature this late into the release cycle.This is an automatic backport of pull request #12410 done by Mergify.