TASK NewLegalMoves allocates a lot

[thejhh]

Note sure if this is really a problem because it should not be called from anywhere else but already optimized memory pooling (board data creation). However, it is top 1.

func NewLegalMoves (indexSize int) chesstypes.LegalMoves {
	ret := make(chesstypes.LegalMoves, indexSize)
	for i := range ret {
		ret[i] = make(chesstypes.IndexList, 0, indexSize)
	}
	return ret[:0]
}

This allocates a lot (top 1):

$ go tool pprof  -alloc_objects mem.prof
Showing top 10 nodes out of 20
      flat  flat%   sum%        cum   cum%
    133124 94.46% 94.46%     133124 94.46%  chess/internal/chessboard.NewLegalMoves (inline)
      6554  4.65% 99.11%       6554  4.65%  chess/internal/chessai/advancedchesscomputer.NewMinimaxJob (inline)
      1024  0.73% 99.84%     134148 95.18%  chess/internal/chessboard.NewBulkGameBoard

The loop is the problem:

(pprof) list NewLegalMoves
Total: 140934
ROUTINE ======================== chess/internal/chessboard.NewLegalMoves in /Users/jhh/git/hangovergames/chess/internal/chessboard/gameboard.go
    133124     133124 (flat, cum) 94.46% of Total
         .          .     84:func NewLegalMoves (indexSize int) chesstypes.LegalMoves {
      2051       2051     85:	ret := make(chesstypes.LegalMoves, indexSize)
         .          .     86:	for i := range ret {
    131073     131073     87:		ret[i] = make(chesstypes.IndexList, 0, indexSize)
         .          .     88:	}
         .          .     89:	return ret[:0]
         .          .     90:}
         .          .     91:
         .          .     92:func NewBulkGameBoard(width, height chesstypes.BoardIndex) *GameBoard {

Showing top 10 nodes out of 26
      flat  flat%   sum%        cum   cum%
11782.63kB 84.72% 84.72% 11782.63kB 84.72%  chess/internal/chessboard.NewLegalMoves (inline)
  587.37kB  4.22% 88.95%   587.37kB  4.22%  github.com/hyperifyio/statelessdb/pkg/logs.NewLogger
  513.12kB  3.69% 92.63%   513.12kB  3.69%  chess/internal/chessai/advancedchesscomputer.filterAvailableMoves
  512.25kB  3.68% 96.32% 12294.88kB 88.41%  chess/internal/chessboard.NewBulkGameBoard
  512.04kB  3.68%   100%   512.04kB  3.68%  chess/internal/chessai/advancedchesscomputer.NewMinimaxJob (inline)

(pprof) list NewLegalMoves
Total: 13.58MB
ROUTINE ======================== chess/internal/chessboard.NewLegalMoves in /Users/jhh/git/hangovergames/chess/internal/chessboard/gameboard.go
   11.51MB    11.51MB (flat, cum) 84.72% of Total
         .          .     84:func NewLegalMoves (indexSize int) chesstypes.LegalMoves {
    3.51MB     3.51MB     85:	ret := make(chesstypes.LegalMoves, indexSize)
         .          .     86:	for i := range ret {
       8MB        8MB     87:		ret[i] = make(chesstypes.IndexList, 0, indexSize)
         .          .     88:	}
         .          .     89:	return ret[:0]
         .          .     90:}
         .          .     91:
         .          .     92:func NewBulkGameBoard(width, height chesstypes.BoardIndex) *GameBoard {