[Impeller] dont increment shared_ptr when tracked object is already tracked. #56153
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| tracked_objects_.emplace_back(std::move(object)); | ||
| tracked_objects_.emplace_back(object); |
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This is incrementing now. The thesis is that this increment matches the one we are replacing when we grab a const ref and in the case where we leave early we avoid the increment altogether? SGTM. I wish we had settings on that required an explicit copy here.
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Yeah, though I found from tracing that we still have multiple share_ptr decrements per draw because the buffer_view emplacement also does a move still. I will send a separate patch for that
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…157736) flutter/engine@bf5bfee...23b2c6d 2024-10-28 [email protected] [Impeller] dont increment shared_ptr when tracked object is already tracked. (flutter/engine#56153) 2024-10-28 [email protected] Roll Dart SDK from a75848f92210 to 69b50768d733 (2 revisions) (flutter/engine#56168) 2024-10-28 [email protected] Roll Skia from 263c3e2ecd30 to f08fbc465888 (1 revision) (flutter/engine#56170) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
…racked. (flutter/engine#56153) By passing the shared_ptrs to TrackedObjectsVK by value, we will always require at least a decrement of the shared_ptr count, and possibly an increment too. Since for most cases the tracked object has already been tracked, passing by const ref results in no increment or decrement. Ignoring the time value, since this is a flamegraph, we can see almost all time spent tracking is spent on shared_ptr decrement: 
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By passing the shared_ptrs to TrackedObjectsVK by value, we will always require at least a decrement of the shared_ptr count, and possibly an increment too.
Since for most cases the tracked object has already been tracked, passing by const ref results in no increment or decrement.
Ignoring the time value, since this is a flamegraph, we can see almost all time spent tracking is spent on shared_ptr decrement: