Phase 68: PGO training set diversification (seed/WS expansion)

Changes:
- scripts/box/pgo_fast_profile_config.sh: Expanded WS patterns (3→5) and seeds (1→3)
  for reduced overfitting and better production workload representativeness
- PERFORMANCE_TARGETS_SCORECARD.md: Phase 68 baseline promoted (61.614M = 50.93%)
- CURRENT_TASK.md: Phase 68 marked complete, Phase 67a (layout tax forensics) set Active

Results:
- 10-run verification: +1.19% vs Phase 66 baseline (GO, >+1.0% threshold)
- M1 milestone: 50.93% of mimalloc (target 50%, exceeded by +0.93pp)
- Stability: 10-run mean/median with <2.1% CV

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

scripts/box/pgo_fast_profile_config.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+# Box: PGO Profile Configuration (FAST minimal)
+# Purpose: Define representative workloads for FAST minimal PGO collection.
+# Contract:
+# - Only deterministic workloads (fixed args/seeds).
+# - Must complete quickly per workload (PGO box enforces timeout).
+# - Keep baseline toolchain consistent (GCC + LTO; profile-generate/use handled by Makefile).
+
+# Binaries to profile (must exist after `make pgo-fast-profile`)
+PGO_BINARIES=(
+    "./bench_random_mixed_hakmem"
+    "./bench_tiny_hot_hakmem"
+)
+
+# Representative workloads (deterministic).
+#
+# Notes:
+# - Keep these as shell strings: pgo_tiny_profile_box.sh runs them via `bash -lc`.
+# - Prefer the same (iter, ws, seed) shape as the canonical Mixed 10-run, but shorter.
+#
+# Phase 68 Update: Diversify WS and seeds to reduce overfitting.
+# - Mixed WS: Added 100, 256, 512, 1024 to existing 400 (5 patterns total).
+# - Tiny hot: Added seed variants 60001, 60002 to 60000 (3 seeds total).
+PGO_WORKLOADS=(
+    # Mixed: run via cleanenv to match benchmark presets (prevents PGO mismatch).
+    # Keep runs small; collector enforces per-workload timeout.
+    # Expanded WS range: 100, 256, 400, 512, 1024 (was: 128, 400, 800)
+    "HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE RUNS=2 ITERS=20000000 WS=100 BENCH_BIN=./bench_random_mixed_hakmem scripts/run_mixed_10_cleanenv.sh"
+    "HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE RUNS=2 ITERS=20000000 WS=256 BENCH_BIN=./bench_random_mixed_hakmem scripts/run_mixed_10_cleanenv.sh"
+    "HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE RUNS=2 ITERS=20000000 WS=400 BENCH_BIN=./bench_random_mixed_hakmem scripts/run_mixed_10_cleanenv.sh"
+    "HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE RUNS=2 ITERS=20000000 WS=512 BENCH_BIN=./bench_random_mixed_hakmem scripts/run_mixed_10_cleanenv.sh"
+    "HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE RUNS=2 ITERS=20000000 WS=1024 BENCH_BIN=./bench_random_mixed_hakmem scripts/run_mixed_10_cleanenv.sh"
+
+    # Tiny hot: C0-ish (16B) and C3-ish (64B) patterns with seed diversification.
+    # Extended seed set: 60000, 60001, 60002 (was: 60000 only)
+    "./bench_tiny_hot_hakmem 16 100 60000"
+    "./bench_tiny_hot_hakmem 16 100 60001"
+    "./bench_tiny_hot_hakmem 16 100 60002"
+    "./bench_tiny_hot_hakmem 64 100 60000"
+    "./bench_tiny_hot_hakmem 64 100 60001"
+    "./bench_tiny_hot_hakmem 64 100 60002"
+)
+
+# Configuration summary
+PGO_WORKLOAD_COUNT=${#PGO_WORKLOADS[@]}
+PGO_BINARY_COUNT=${#PGO_BINARIES[@]}

scripts/box/pgo_tiny_profile_box.sh

@@ -10,7 +10,8 @@
 set -e  # Fail fast on errors
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-source "${SCRIPT_DIR}/pgo_tiny_profile_config.sh"
+PGO_CONFIG_BASENAME="${PGO_CONFIG:-pgo_tiny_profile_config.sh}"
+source "${SCRIPT_DIR}/${PGO_CONFIG_BASENAME}"
 
 echo "========================================="
 echo "Box: PGO Profile Collection (Tiny Front)"
@@ -18,6 +19,7 @@ echo "========================================="
 echo "Date: $(date)"
 echo "Workloads: $PGO_WORKLOAD_COUNT"
 echo "Binaries: $PGO_BINARY_COUNT"
+echo "Config: $PGO_CONFIG_BASENAME"
 echo ""
 
 # Validate binaries exist and are executable
@@ -58,7 +60,7 @@ for workload in "${PGO_WORKLOADS[@]}"; do
     echo "-------------------------------------------"
 
     # Execute with timeout (30s per workload)
-    if timeout 30 $workload; then
+    if timeout 30 bash -lc "$workload"; then
         echo "  ✓ Success"
     else
         EXIT_CODE=$?