mapleFU commented on code in PR #6155:
URL: https://github.com/apache/arrow-rs/pull/6155#discussion_r1717351091
##########
arrow-buffer/src/buffer/null.rs:
##########
@@ -131,9 +176,20 @@ impl NullBuffer {
}
/// Returns the null count for this [`NullBuffer`]
- #[inline]
pub fn null_count(&self) -> usize {
- self.null_count
+ match &self.null_count {
+ NullCount::Eager(v) => *v,
+ NullCount::Lazy(v) => {
+ let cached_null_count = v.load(Ordering::Acquire);
+ if cached_null_count != UNINITIALIZED_NULL_COUNT {
+ return cached_null_count as usize;
+ }
+
+ let computed_null_count = self.buffer.len() -
self.buffer.count_set_bits();
+ v.store(computed_null_count as i64, Ordering::Release);
Review Comment:
> It may hurt the cpu cache, too? But I know few about the detial.
Comparing to Relaxed, Acq-Rel would just re-ordering in x86, but in weak
ordering machine it might affect the cache an would require memory barrier or
other instr
--
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: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
