gqa(milestone-1h-gqa): add umbrella bench + first sweep outputs

Single @bench entry that drives the prefill + decode long-context
4-cases sweeps in one invocation, mirroring milestone-1h-gemm. The
individual gqa_helpers/long_ctx/gqa_{prefill,decode}_long_ctx_4cases
modules are now pure helpers (no @bench), reached only via this
umbrella.

Env var contract:
  GQA_1H_RUN=1                    (required gate)
  GQA_1H_SWEEPS=prefill,decode    (default: both; pick subset to skip)
  GQA_1H_TOPOLOGY=topology.yaml   (override)

Output layout:
  benches/1H_milestone_output/gqa/long_ctx/
    sweep_prefill.json
    sweep_decode.json
    gqa_prefill_long_ctx_4cases_{latency,traffic,memory,parallelism}.png
    gqa_decode_long_ctx_4cases_{latency,traffic,memory,parallelism}.png

The decode bench config drops S_kv from 131_072 to 8_192 so the umbrella
finishes in minutes — the comparative-story bars are the same shape at
8K. The 131K production headline number is recoverable by overriding
the dispatch; the helper docstring notes this.

Outputs (2 sweep JSONs + 8 PNGs) ship in this commit alongside the
umbrella that produced them, following the milestone-1h-gemm pattern
where derived artifacts live with the bench that emits them.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/kernbench/benches/1H_milestone_output/gqa/long_ctx/sweep_decode.json

@@ -0,0 +1,115 @@
+{
+  "version": 1,
+  "panels": [
+    "single_kv_group_decode_long_ctx_gqa_cube_sp_pe_sp",
+    "single_kv_group_decode_long_ctx_gqa_cube_repl_pe_tp",
+    "single_kv_group_decode_long_ctx_gqa_cube_repl_pe_sp",
+    "single_kv_group_decode_long_ctx_gqa_cube_sp_pe_tp"
+  ],
+  "rows": [
+    {
+      "panel": "single_kv_group_decode_long_ctx_gqa_cube_sp_pe_sp",
+      "kind": "decode_long_ctx_cube_sp_pe_sp",
+      "C": 8,
+      "P": 8,
+      "T_q": 1,
+      "S_kv": 8192,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 128,
+        "ipcq_copy_count": 189,
+        "dma_read_count": 192,
+        "dma_write_count": 1
+      },
+      "latency_ns": 34030.00300000079,
+      "engine_occupancy_ns": {
+        "pe_gemm": 4194.303999999538,
+        "pe_math": 2282.0,
+        "pe_dma": 1138201.8199999991,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_decode_long_ctx_gqa_cube_repl_pe_tp",
+      "kind": "decode_long_ctx_cube_repl_pe_tp",
+      "C": 8,
+      "P": 8,
+      "T_q": 1,
+      "S_kv": 8192,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 16,
+        "ipcq_copy_count": 0,
+        "dma_read_count": 17,
+        "dma_write_count": 1
+      },
+      "latency_ns": 25428.38200085424,
+      "engine_occupancy_ns": {
+        "pe_gemm": 4194.303999997675,
+        "pe_math": 714.0,
+        "pe_dma": 18217.080000881106,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_decode_long_ctx_gqa_cube_repl_pe_sp",
+      "kind": "decode_long_ctx_cube_repl_pe_sp",
+      "C": 8,
+      "P": 8,
+      "T_q": 1,
+      "S_kv": 8192,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 128,
+        "ipcq_copy_count": 168,
+        "dma_read_count": 192,
+        "dma_write_count": 1
+      },
+      "latency_ns": 20152.09400000231,
+      "engine_occupancy_ns": {
+        "pe_gemm": 33554.431999996305,
+        "pe_math": 5684.0,
+        "pe_dma": 853218.7100000716,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_decode_long_ctx_gqa_cube_sp_pe_tp",
+      "kind": "decode_long_ctx_cube_sp_pe_tp",
+      "C": 8,
+      "P": 8,
+      "T_q": 1,
+      "S_kv": 8192,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 16,
+        "ipcq_copy_count": 21,
+        "dma_read_count": 24,
+        "dma_write_count": 1
+      },
+      "latency_ns": 26987.291500001098,
+      "engine_occupancy_ns": {
+        "pe_gemm": 4194.303999999538,
+        "pe_math": 714.0,
+        "pe_dma": 126624.99000000354,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    }
+  ]
+}

src/kernbench/benches/1H_milestone_output/gqa/long_ctx/sweep_prefill.json

@@ -0,0 +1,116 @@
+{
+  "version": 1,
+  "panels": [
+    "single_kv_group_prefill_long_ctx_gqa_cube_sp_pe_sp",
+    "single_kv_group_prefill_long_ctx_gqa_cube_repl_pe_tp",
+    "single_kv_group_prefill_long_ctx_gqa_cube_repl_pe_sp",
+    "single_kv_group_prefill_long_ctx_gqa_cube_sp_pe_tp"
+  ],
+  "rows": [
+    {
+      "panel": "single_kv_group_prefill_long_ctx_gqa_cube_sp_pe_sp",
+      "kind": "prefill_long_ctx_cube_sp_pe_sp",
+      "C": 8,
+      "P": 8,
+      "T_q": 512,
+      "S_kv": 512,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 1024,
+        "ipcq_copy_count": 1064,
+        "dma_read_count": 192,
+        "dma_write_count": 8
+      },
+      "latency_ns": 86702.76799999712,
+      "engine_occupancy_ns": {
+        "pe_gemm": 134217.72799998685,
+        "pe_math": 546656.0,
+        "pe_dma": 2388650.3709999938,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_prefill_long_ctx_gqa_cube_repl_pe_tp",
+      "kind": "prefill_long_ctx_cube_repl_pe_tp",
+      "C": 8,
+      "P": 8,
+      "T_q": 512,
+      "S_kv": 512,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 1024,
+        "ipcq_copy_count": 0,
+        "dma_read_count": 1088,
+        "dma_write_count": 64
+      },
+      "latency_ns": 93564.33200003332,
+      "engine_occupancy_ns": {
+        "pe_gemm": 134217.72799998525,
+        "pe_math": 81279.99999999997,
+        "pe_dma": 177951.73600022023,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_prefill_long_ctx_gqa_cube_repl_pe_sp",
+      "kind": "prefill_long_ctx_cube_repl_pe_sp",
+      "C": 8,
+      "P": 8,
+      "T_q": 512,
+      "S_kv": 512,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 8192,
+        "ipcq_copy_count": 10752,
+        "dma_read_count": 12288,
+        "dma_write_count": 64
+      },
+      "latency_ns": 190579.57100032456,
+      "engine_occupancy_ns": {
+        "pe_gemm": 1073741.8240003586,
+        "pe_math": 635904.0,
+        "pe_dma": 1756854.05751659,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    },
+    {
+      "panel": "single_kv_group_prefill_long_ctx_gqa_cube_sp_pe_tp",
+      "kind": "prefill_long_ctx_cube_sp_pe_tp",
+      "C": 8,
+      "P": 8,
+      "T_q": 512,
+      "S_kv": 512,
+      "d_head": 128,
+      "h_q": 8,
+      "h_kv": 1,
+      "op_log_summary": {
+        "gemm_count": 1024,
+        "ipcq_copy_count": 896,
+        "dma_read_count": 192,
+        "dma_write_count": 64
+      },
+      "latency_ns": 38876.32300000038,
+      "engine_occupancy_ns": {
+        "pe_gemm": 134217.7280000001,
+        "pe_math": 81280.0,
+        "pe_dma": 916284.0330000015,
+        "pe_fetch_store": 0,
+        "pe_ipcq": 0,
+        "pe_cpu": 0
+      }
+    }
+  ],
+  "failures": []
+}