[Bug libstdc++/113504] High memory usage for parallel `std::sort`

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113504

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #7)
> So the PSTL versions still use nearly twice as much memory as TBB and the
> sequential sorts, but that factor is constant; it doesn't grow with the size
> of the input.

The PSTL version is also nearly twice as fast as TBB, so the additional memory
seems like a good trade off.