remove unused kh_del, pack kh_hash flag bits #2572
Closed
Conversation
This file contains hidden or 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
|
This is great. Thanks for digging deep on this one; I would like to replace the usage of khash at some point with an even leaner hash table implementation, but this gives nice performance gains for now. |
|
I would chalk up the time increases at the bottom to memory allocation /OS issues |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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.
The kh_hash library includes the ability to delete elements, but this is not used anywhere in pandas. In the khash library, there are two flags bits for every entry: ''isempty' and 'isdel'. This change removes the support for kh_del from the khash library, allowing it to use half as many flag bits.
All tests pass. I ran test_perf ~90 times, and got the results below (baseline = parent commit, times and ratios ± stdev). There do seem to be a few (at the bottom) whose times increase slightly, which surprises me.