jorgecarleitao opened a new pull request #9076: URL: https://github.com/apache/arrow/pull/9076
This PR refactors `MutableBuffer::extend_from_slice` to remove the need to use `to_byte_slice` on every call, thereby removing its level of indirection, that does not allow the compiler to optimize out some code. This is the second performance improvement originally presented in #8796 and, together with #9027 , brings the performance of "MutableBuffer" to the same level as `Vec<u8>`, in particular to building buffers on the fly. Basically, when converting to a byte slice `&[u8]`, the compiler lost the type size information, and thus needs to perform extra checks and can't just optimize out the code. This PR adopts the same API as `Vec<T>::extend_from_slice`, but since our buffers are in `u8` (i.e. a la `Vec<u8>`), I made the signature ``` pub fn extend_from_slice<T: ToByteSlice>(&mut self, items: &[T]) pub fn push<T: ToByteSlice>(&mut self, item: &T) ``` i.e. it consumes something that can be converted to a byte slice, but internally makes the conversion to bytes (as `to_byte_slice` was doing). Credits for the root cause analysis that lead to this PR go to @Dandandan, [originally fielded here](https://github.com/apache/arrow/pull/9016#discussion_r549110164). > [...] current conversion to a byte slice may add some overhead? - @Dandandan ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
