diff --git a/experiments/910c/glm52_910c_vllm_tp_dp_matrix/adaptive_config.env b/experiments/910c/glm52_910c_vllm_tp_dp_matrix/adaptive_config.env
index 3b05c7c..ce122ad 100644
--- a/experiments/910c/glm52_910c_vllm_tp_dp_matrix/adaptive_config.env
+++ b/experiments/910c/glm52_910c_vllm_tp_dp_matrix/adaptive_config.env
@@ -19,8 +19,10 @@ TPS_MIN_GAIN_PCT="${TPS_MIN_GAIN_PCT:-2.0}"
 PLATEAU_PATIENCE="${PLATEAU_PATIENCE:-2}"
 
 # TTFT SLO early-stop settings.
-# When ttft_p95_ms exceeds TTFT_SLO_MS, stop searching the current (ISL, OSL)
+# When ttft_p95_ms exceeds the SLO, stop searching the current (ISL, OSL)
 # shape and move on to the next scenario.
+# TTFT_SLO_MS is the flat fallback; if config.env defines get_ttft_slo_ms(),
+# the per-ISL tiered SLO returned by that function takes precedence.
 TTFT_SLO_MS="${TTFT_SLO_MS:-4000}"
 ENABLE_TTFT_SLO_STOP="${ENABLE_TTFT_SLO_STOP:-1}"
 
diff --git a/experiments/910c/glm52_910c_vllm_tp_dp_matrix/config.env b/experiments/910c/glm52_910c_vllm_tp_dp_matrix/config.env
index e2ab628..fb65300 100644
--- a/experiments/910c/glm52_910c_vllm_tp_dp_matrix/config.env
+++ b/experiments/910c/glm52_910c_vllm_tp_dp_matrix/config.env
@@ -117,3 +117,22 @@ GPU_MEM_SAMPLE_INTERVAL_S="${GPU_MEM_SAMPLE_INTERVAL_S:-1}"
 
 DRY_RUN="${DRY_RUN:-0}"
 GRID_LIMIT="${GRID_LIMIT:-0}"
+
+# ---------------------------------------------------------------------------
+# Tiered TTFT SLO by input sequence length.
+# GLM-5.2 (w4a8c8) has simpler architecture than DSv4-Pro (no MLA/DeepSeek MoE),
+# so its SLO thresholds are set slightly lower (~70-80% of DSv4-Pro values).
+# This function is called by adaptive_bench_lib.sh during the concurrency
+# sweep: when ttft_p95_ms exceeds the returned SLO, the current ISL/OSL shape
+# search stops.
+# ---------------------------------------------------------------------------
+get_ttft_slo_ms() {
+  local isl="$1"
+  if   (( isl <= 2048 ));   then echo 5000
+  elif (( isl <= 8192 ));   then echo 8000
+  elif (( isl <= 32768 ));  then echo 12000
+  elif (( isl <= 131072 )); then echo 20000
+  else                           echo 30000
+  fi
+}
+TTFT_SLO_TIERS_DESC="≤2048:5000ms, ≤8192:8000ms, ≤32768:12000ms, ≤131072:20000ms, >131072:30000ms"
diff --git a/scripts/common/adaptive_bench_lib.sh b/scripts/common/adaptive_bench_lib.sh
index 10c4e84..a357757 100755
--- a/scripts/common/adaptive_bench_lib.sh
+++ b/scripts/common/adaptive_bench_lib.sh
@@ -96,6 +96,19 @@ adaptive_validate_config() {
   done
 }
 
+# ---------------------------------------------------------------------------
+# Per-ISL TTFT SLO lookup (tiered SLO support).
+# Experiments can override this by defining get_ttft_slo_ms() in their
+# config.env BEFORE sourcing this library.  The default implementation
+# returns the flat TTFT_SLO_MS value, preserving backward compatibility.
+# ---------------------------------------------------------------------------
+if ! declare -f get_ttft_slo_ms >/dev/null 2>&1; then
+  get_ttft_slo_ms() {
+    local isl="$1"
+    echo "${TTFT_SLO_MS:-4000}"
+  }
+fi
+
 adaptive_start_gpu_monitor() {
   local csv_path="$1"
   mkdir -p "$(dirname "$csv_path")"
@@ -439,7 +452,9 @@ adaptive_run_shape() {
       local ttft_p95_ms=""
       if [[ "${ENABLE_TTFT_SLO_STOP:-1}" == "1" ]]; then
         ttft_p95_ms="$("$PYTHON" -c 'import json, sys; print(json.load(open(sys.argv[1]))["ttft_p95_ms"])' "$POINT_METRICS_FILE")"
-        if awk -v ttft="$ttft_p95_ms" -v slo="${TTFT_SLO_MS:-4000}" 'BEGIN { exit !(ttft > slo) }'; then
+        local slo_ms
+        slo_ms=$(get_ttft_slo_ms "$isl")
+        if awk -v ttft="$ttft_p95_ms" -v slo="$slo_ms" 'BEGIN { exit !(ttft > slo) }'; then
           adaptive_append_point_from_metrics \
             "$POINT_METRICS_FILE" "$tp" "$dp" "$mark" "$isl" "$osl" \
             "$concurrency" "$num_prompts" "$POINT_ATTEMPT" "$gain_pct" \
@@ -455,7 +470,7 @@ adaptive_run_shape() {
             done
           fi
           if [[ -n "$next_backoff" ]]; then
-            log "probe result c=${concurrency} total_tps=${current_tps} ttft_p95=${ttft_p95_ms}ms > SLO=${TTFT_SLO_MS}ms; retrying initial boundary at c=${next_backoff}"
+            log "probe result c=${concurrency} total_tps=${current_tps} ttft_p95=${ttft_p95_ms}ms > SLO=${slo_ms}ms (isl=${isl}); retrying initial boundary at c=${next_backoff}"
             initial_backoff_active=1
             initial_backoff_reason="TTFT"
             concurrency="$next_backoff"
@@ -476,7 +491,7 @@ adaptive_run_shape() {
           fi
           stop_reason="TTFT_SLO_EXCEEDED"
           shape_status="TTFT_BOUNDARY"
-          log "probe result c=${concurrency} total_tps=${current_tps} ttft_p95=${ttft_p95_ms}ms > SLO=${TTFT_SLO_MS}ms, stopping shape"
+          log "probe result c=${concurrency} total_tps=${current_tps} ttft_p95=${ttft_p95_ms}ms > SLO=${slo_ms}ms (isl=${isl}), stopping shape"
           break
         fi
       fi
@@ -826,6 +841,7 @@ adaptive_main() {
     "${TTFT_SLO_MS:-4000}" \
     "${ENABLE_TTFT_SLO_STOP:-1}" \
     "${TTFT_GROUP_SKIP_MS:-0}" \
+    "${TTFT_SLO_TIERS_DESC:-}" \
     > "${ADAPTIVE_RUN_ROOT}/run_manifest.json" <<'PY'
 import json, sys
 
@@ -833,7 +849,8 @@ import json, sys
  tokenize_prompt, random_range_ratio, search_start, search_cap,
  search_multiplier, initial_backoff_concurrencies, prompts_multiplier,
  min_gain_pct, plateau_patience, warmup_max_requests, ttft_slo_ms,
- enable_ttft_slo_stop, ttft_group_skip_ms) = sys.argv[1:21]
+ enable_ttft_slo_stop, ttft_group_skip_ms,
+ ttft_slo_tiers_desc) = sys.argv[1:22]
 
 print(json.dumps({
     "experiment": experiment,
@@ -857,6 +874,7 @@ print(json.dumps({
         "plateau_patience": int(plateau_patience),
         "warmup_max_requests": int(warmup_max_requests),
         "ttft_slo_ms": float(ttft_slo_ms),
+        "ttft_slo_tiers_desc": ttft_slo_tiers_desc,
         "enable_ttft_slo_stop": int(enable_ttft_slo_stop),
         "ttft_group_skip_ms": float(ttft_group_skip_ms),
     },