From 5883f5a64f4f464b877b7637b8e13c25f7d208fc Mon Sep 17 00:00:00 2001 From: Scott Gasch Date: Fri, 4 Sep 2026 23:54:51 -0700 Subject: Add Eval() bitboard-migration plan, per-term EVAL_TIME cycle breakdown, drop redundant pawn-location bitboard board_representation/EVAL.md: rewritten migration plan for a bitboard-backed Eval() (mobility ray-walks + bvAttacks replacement), plus a performance-philosophy section recording the profiling-first, cut-aggressively-except-mobility/safety-awareness approach agreed on this session, and findings on CountKingSafetyDefects' structural inability to share bvAttacks-derived state with _EvalKing. EVAL_TIME per-term instrumentation (chess.h/eval.c/root.c): breaks the existing whole-Eval() cycle counter down by pawns/knight/bishop/ rook/queen/king, the always-paid pre-lazy-exit segment, and the full-eval-only post-lazy segment, printed alongside the existing "Avg. cpu cycles in eval" line. Diagnostic only (EVAL_TIME-gated), no effect on the normal release profile. Drop PAWN_HASH_ENTRY's bbPawnLocations[2]: it duplicated POSITION's own incrementally-maintained bbPawns[2], rebuilt bit-by-bit on every pawn-hash miss for no reason. eval.c now reads pos->bbPawns[] directly; removed a stale per-iteration invariant assert in _EvalPawns that only made sense when the bitboard was being built bit-by-bit in that same loop. Co-Authored-By: Claude Sonnet 5 Claude-Session: https://claude.ai/code/session_01P6g6iF6mD1Hau6nCZCzwYj --- src/root.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'src/root.c') diff --git a/src/root.c b/src/root.c index bfcf034..5ce4c9e 100755 --- a/src/root.c +++ b/src/root.c @@ -563,6 +563,58 @@ Return value: #ifdef EVAL_TIME n = (double)ctx->sCounters.tree.u64CyclesInEval; Trace("Avg. cpu cycles in eval: %8.1f.\n", (n / d)); + { + // + // Per-term breakdown of the average above -- board_ + // representation/EVAL.md section 0b. "other" covers every + // term not individually timed (pawn structure detail beyond + // _EvalPawns' own bucket, bishop pairs, bad-trade/passer-race + // detection, lazy-eval margin estimation, etc.) computed as + // the remainder rather than its own counter, so this always + // sums exactly to the total above regardless of what future + // terms get their own bucket. + // + UINT64 u64Pawns = ctx->sCounters.tree.u64CyclesEvalPawns; + UINT64 u64Knight = ctx->sCounters.tree.u64CyclesEvalKnight; + UINT64 u64Bishop = ctx->sCounters.tree.u64CyclesEvalBishop; + UINT64 u64Rook = ctx->sCounters.tree.u64CyclesEvalRook; + UINT64 u64Queen = ctx->sCounters.tree.u64CyclesEvalQueen; + UINT64 u64King = ctx->sCounters.tree.u64CyclesEvalKing; + // + // u64PreLazy already contains u64Pawns as a subset (pawns + // runs nested inside the pre-lazy segment, not after it) -- + // split it out here rather than double-counting both. + // + UINT64 u64PreLazy = ctx->sCounters.tree.u64CyclesEvalPreLazy; + UINT64 u64PreLazyOther = (u64PreLazy >= u64Pawns) ? + (u64PreLazy - u64Pawns) : 0; + UINT64 u64PostMisc = ctx->sCounters.tree.u64CyclesEvalPostLazyMisc; + UINT64 u64AttackPop = ctx->sCounters.tree.u64CyclesEvalAttackTablePop; + UINT64 u64Named = (u64PreLazy + u64Knight + u64Bishop + + u64Rook + u64Queen + u64King + u64PostMisc + + u64AttackPop); + UINT64 u64Total = ctx->sCounters.tree.u64CyclesInEval; + UINT64 u64Unaccounted = (u64Total >= u64Named) ? + (u64Total - u64Named) : 0; + + Trace(" eval breakdown (%% of total cycles in eval):\n"); + Trace(" pre-lazy (always paid): %5.1f%% " + "(of which pawns: %5.1f%%, other pre-lazy: %5.1f%%)\n", + (u64Total ? (100.0 * (double)u64PreLazy / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64Pawns / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64PreLazyOther / (double)u64Total) : 0.0)); + Trace(" knight: %5.1f%% bishop: %5.1f%% rook: %5.1f%%\n", + (u64Total ? (100.0 * (double)u64Knight / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64Bishop / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64Rook / (double)u64Total) : 0.0)); + Trace(" queen: %5.1f%% king: %5.1f%% post-lazy misc: %5.1f%%\n", + (u64Total ? (100.0 * (double)u64Queen / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64King / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64PostMisc / (double)u64Total) : 0.0)); + Trace(" attack-table pop: %5.1f%% unaccounted: %5.1f%%\n", + (u64Total ? (100.0 * (double)u64AttackPop / (double)u64Total) : 0.0), + (u64Total ? (100.0 * (double)u64Unaccounted / (double)u64Total) : 0.0)); + } #endif #endif } -- cgit v1.3