Edarke commented on PR #13581: URL: https://github.com/apache/lucene/pull/13581#issuecomment-2266355062
> > @msokolov Sorry to interject, but the hash function Objects.hash(level, node) % NUM_LOCKS; seems like it is prone to lock contention if workers have power of 2 offsets. Would it be worthwhile to avoid the Integer[] allocation and smear the hash instead? > > Thanks for interjection! I'm sorry, but I don't really understand. Which Integer[] allocation did you mean? Ah sorry, I was referring to the varargs invocation of `Objects.hash(Object...)` implicitly boxing the primitive ints. Not sure if that's a concern, but `Objects.hash` produces low entropy in the lower bits, which is ordinarily fine because collections like `HashMap` will smear hashCodes before computing array indexes. ```java int lockid = Objects.hash(level, node) % NUM_LOCKS; ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
