Cleanup to prepare for using mmap pointer in external memory. #9317
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
hcho3
reviewed
Jun 21, 2023
| @@ -70,8 +73,9 @@ struct BitFieldContainer { | |||
| }; | |||
|
|
|||
| private: | |||
| common::Span<value_type> bits_; | |||
| static_assert(!std::is_signed<VT>::value, "Must use unsiged type as underlying storage."); | |||
| value_type* bits_{nullptr}; | |||
There was a problem hiding this comment.
Can you explain why we should use a raw pointer here? You mentioned the use of std::vector<bool> in ColumnMatrix. Does the span behave badly when value_type == bool ?
There was a problem hiding this comment.
It's used in hot loops, the check used in span can be expensive.
We won't be using std::vector<bool> after #9315 . In that PR, I have defined a reference counted view that's a replacement for std::vector, with the ability that we can swap out the underlying storage when needed. It doesn't have the bool specialization, therefore, an additional bitfield is used.
hcho3
approved these changes
Jun 21, 2023
1 task
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
Extracted from #9315 .
std::vector<bool>inColumnMatrixwith bitfield.