feat(kvc): add backpressure smoke sweep + analyzer (and v6 p1 profile script)

scripts/sweep_backpressure_smoke.sh: 4-run smoke matrix (KVC baseline /
KVC + backpressure / KVC + backpressure @ time-scale=1 / DP @
time-scale=1) designed to fit ~3-4h GPU budget. Validates §3 backpressure
implementation and partially probes §7 time-scale distortion.

scripts/analysis/analyze_backpressure_smoke.py: consumes the new
structural/* jsonl files plus request-metrics; emits headline metrics,
backpressure histograms, admission probe stats, and per-session pinning
distribution.

scripts/sweep_tp1_v6_p1_profile.sh: pre-existing v6 P1 profile sweep
script (was untracked; included for completeness).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/sweep_backpressure_smoke.sh

@@ -0,0 +1,114 @@
+#!/usr/bin/env bash
+# Smoke sweep: validate backpressure code change on top of v5 Option D config.
+# Designed to fit in ~3-4h GPU budget (4 runs × ~30-60 min).
+#
+# Usage:
+#   bash scripts/sweep_backpressure_smoke.sh
+#
+# Prerequisites: GPUs available; trace at outputs/qwen35-swebench-50sess.jsonl;
+# model at $MODEL_PATH (default Qwen3-30B-A3B-Instruct-2507).
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$REPO_ROOT"
+
+OUT_ROOT=${OUT_ROOT:-outputs/sweep_backpressure_smoke}
+TRACE=${TRACE:-outputs/qwen35-swebench-50sess.jsonl}
+MODEL=${MODEL:-/mnt/kzlin/workflow/pd-hybrid/simm-swe-bench/models/Qwen3-30B-A3B-Instruct-2507}
+
+mkdir -p "$OUT_ROOT"
+LOG="$OUT_ROOT/sweep.log"
+echo "[$(date '+%F %T')] Starting backpressure smoke sweep" | tee -a "$LOG"
+echo "  Trace: $TRACE" | tee -a "$LOG"
+echo "  Model: $MODEL" | tee -a "$LOG"
+echo "  Output root: $OUT_ROOT" | tee -a "$LOG"
+
+KVC_COMMON_ARGS=(
+    --trace "$TRACE"
+    --model "$MODEL"
+    --mechanism kvcache-centric
+    --policy kv-aware
+    --kvcache-admission-mode worker
+    --kvcache-seed-min-turn-id 1
+    --kvcache-seed-max-inflight-decode -1
+    --kvcache-prefill-backup-policy release-after-transfer
+    --kvcache-prefill-priority-eviction
+    --prefill-workers 2
+    --decode-workers 6
+    --prefill-gpu-ids 0,1
+    --decode-gpu-ids 2,3,4,5,6,7
+    --transfer-backend mooncake
+    --target-duration-s 2000
+    --session-sample-rate 1.0
+    --min-turns 2
+    --concurrency-limit 32
+)
+
+DP_COMMON_ARGS=(
+    --trace "$TRACE"
+    --model "$MODEL"
+    --mechanism pd-colo
+    --policy kv-aware
+    --direct-workers 8
+    --direct-gpu-ids 0,1,2,3,4,5,6,7
+    --transfer-backend mooncake
+    --target-duration-s 2000
+    --session-sample-rate 1.0
+    --min-turns 2
+    --concurrency-limit 32
+)
+
+run_kvc_baseline_ts10() {
+    local out="$OUT_ROOT/E1_kvc_baseline_ts10"
+    echo "[$(date '+%F %T')] === E1: KVC baseline (no backpressure) time-scale=10 ===" | tee -a "$LOG"
+    python -m agentic_pd_hybrid.cli benchmark-live \
+        "${KVC_COMMON_ARGS[@]}" \
+        --output-root "$out" \
+        --time-scale 10 \
+        2>&1 | tee -a "$LOG"
+}
+
+run_kvc_backpressure_ts10() {
+    local out="$OUT_ROOT/E2_kvc_backpressure_ts10"
+    echo "[$(date '+%F %T')] === E2: KVC + backpressure ON, time-scale=10 ===" | tee -a "$LOG"
+    python -m agentic_pd_hybrid.cli benchmark-live \
+        "${KVC_COMMON_ARGS[@]}" \
+        --output-root "$out" \
+        --time-scale 10 \
+        --enable-backpressure \
+        --backpressure-max-pause-s 2.0 \
+        2>&1 | tee -a "$LOG"
+}
+
+run_kvc_backpressure_ts1() {
+    local out="$OUT_ROOT/E3_kvc_backpressure_ts1_short"
+    echo "[$(date '+%F %T')] === E3: KVC + backpressure ON, time-scale=1, FIRST 1000 reqs ===" | tee -a "$LOG"
+    python -m agentic_pd_hybrid.cli benchmark-live \
+        "${KVC_COMMON_ARGS[@]}" \
+        --output-root "$out" \
+        --time-scale 1 \
+        --enable-backpressure \
+        --backpressure-max-pause-s 2.0 \
+        --target-duration-s 1800 \
+        2>&1 | tee -a "$LOG"
+}
+
+run_dp_baseline_ts1() {
+    local out="$OUT_ROOT/E4_dp_ts1_short"
+    echo "[$(date '+%F %T')] === E4: 8-way DP cache-aware, time-scale=1, FIRST 1000 reqs ===" | tee -a "$LOG"
+    python -m agentic_pd_hybrid.cli benchmark-live \
+        "${DP_COMMON_ARGS[@]}" \
+        --output-root "$out" \
+        --time-scale 1 \
+        --target-duration-s 1800 \
+        2>&1 | tee -a "$LOG"
+}
+
+# Sequence — add/remove as fits the budget.
+run_kvc_baseline_ts10
+run_kvc_backpressure_ts10
+run_kvc_backpressure_ts1
+run_dp_baseline_ts1
+
+echo "[$(date '+%F %T')] === sweep DONE ===" | tee -a "$LOG"
+echo "Run analysis with: python scripts/analysis/analyze_backpressure_smoke.py $OUT_ROOT" | tee -a "$LOG"