[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [JAVA] Arrow performance measurement

Hi Animesh,

Le 26/11/2018 à 14:23, Animesh Trivedi a écrit :
> * C++ bitmap code can be optimized further by using the unsigned integers
> than "int64_t" for bitmap checks, and eliminating the kBitmap. See here
> https://godbolt.org/z/deq0_q - compare the size of the assembly code. And
> the performance measurements in the blog show up to 50% performance gains.
> Alternatively if signed to unsigned upgrade is not possible (perhaps in
> every language), then in the C++ code, we should use the bitmap operations
> directory ( `<<3` for division by 8, and ` & 0x7` for modulo by 8
> operation), instead of `/` and `%`.

Thank you for noticing this.  Switching to unsigned (and do a
static_cast to unsigned) sounds good to me.