Data sharing is required to enable loaned interface on subscription. #726
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Signed-off-by: Tomoya Fujita <Tomoya.Fujita@sony.com>
| subscription->can_loan_messages = info->type_support_->is_plain(); | ||
| bool has_data_sharing = DataSharingKind::OFF != qos.data_sharing().kind(); | ||
| subscription->can_loan_messages = has_data_sharing && info->type_support_->is_plain(); |
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I intentionally did not apply the same change to the publisher, since that is clear that user need to use LoanedMessage class explicitly, and it also provide performance improvement for intra and UDP transport w/o data sharing.
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I think this misses the point that you may want to use messages loaned from the middleware even when you're not doing inter-process zero-copy (so called "DataSharing" with Fast-DDS).
You would also like to use loaned messages to avoid copies, which is why the rclcpp executor uses it by default.
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Edit: you may want your subscription to use messages loaned from the middleware
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yeah that was original intention to enable loaned message w/o DataSharing in Fast-DDS. It still provides the performance improvement for subscription, after ros2/rcl#1110 is merged, probably we do not need this one.
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I will go ahead to close this one, see ros-navigation/navigation2#3863 (comment) for more details. and,
will do the work. |
this is draft PR to try to address,