[{"data":1,"prerenderedAt":170},["ShallowReactive",2],{"run:s2gate-base-12500-r1":3,"run-findings:s2gate-base-12500-r1":137},{"run":4,"config":19,"metrics":82,"curve":88,"assets":136},{"id":5,"title":5,"subtitle":6,"eyebrow":7,"date":8,"workspace":9,"commit":10,"tags":11,"verdict":18},"s2gate-base-12500-r1","S2 gate 同一 session baseline: default スタック 12.5k repeat 1 (S2 arm と交互実行)","Run summary · 2026-08 1× 工程表 v2 — AC 復帰後 計測 queue #2 (S2 gate)","2026-08-16","splat","66f7f34",[12,13,14,15,16,17],"p2-s2-forward-chained","s2","gpu-gate","baseline","no-profile","lego-12500","partial",[20,23,26,29,32,35,38,41,44,47,50,53,56,59,62,65,68,71,74,77,79],{"key":21,"value":22},"dataset","\u002FUsers\u002Fotkrickey\u002Fdev\u002F3dgs-workspace\u002Fdatasets\u002Fnerf_synthetic\u002Flego",{"key":24,"value":25},"gt_convention","Premultiplied",{"key":27,"value":28},"iterations","12,500",{"key":30,"value":31},"seed","42",{"key":33,"value":34},"capacity","1,000,000 splats",{"key":36,"value":37},"sh_degree","3",{"key":39,"value":40},"loss","L1Ssim",{"key":42,"value":43},"lambda","0.200",{"key":45,"value":46},"ssim","window=7 sigma=1",{"key":48,"value":49},"backend.backward","Simd",{"key":51,"value":52},"backend.loss_path","Gpu",{"key":54,"value":55},"backend.emit_pairs","Original",{"key":57,"value":58},"backend.forward","F32",{"key":60,"value":61},"backend.dispatch","PerStage",{"key":63,"value":64},"backend.radix_scan","Cpu",{"key":66,"value":67},"backend.binning","Resident",{"key":69,"value":70},"backend.tile_sort","GlobalRadix",{"key":72,"value":73},"backend.submission","Chained",{"key":75,"value":76},"backend.target_cache","true",{"key":78,"value":76},"backend.shader_fast_math",{"key":80,"value":81},"os_build","26.5.2 (25F84)",{"psnr":83,"wallclock":84,"wallclock_regress":85,"splats":86,"final_loss":87},36.107147216796875,"3m 28s",false,405267,"5.568948e-3",{"loss":89,"splats":120},{"iters":90,"values":105},[91,92,93,94,95,96,97,98,99,100,101,102,103,104],1,1000,2000,3000,4000,5000,6000,7000,8000,9000,10000,11000,12000,12500,[106,107,108,109,110,111,112,113,114,115,116,117,118,119],0.5938454866409302,0.054795004427433014,0.014554998837411404,0.008336791768670082,0.007294791750609875,0.006579806562513113,0.00624232878908515,0.006007627584040165,0.005835834890604019,0.005694585852324963,0.0056597148068249226,0.005549739580601454,0.0054553779773414135,0.005568948108702898,{"iters":121,"values":122},[91,92,93,94,95,96,97,98,99,100,101,102,103,104],[123,124,125,126,127,128,129,130,131,132,133,134,135,86],5207,8240,180828,296502,348373,373949,387983,395403,399509,401626,402670,403467,404592,{"has_renders":85,"has_splat":85},[138],{"id":12,"title":139,"date":8,"status":140,"polarity":141,"category":142,"axes":143,"tags":145,"task_code":157,"related_runs":158,"delta_psnr":164,"delta_wallclock":165,"rank":166,"verdict":167,"impact_summary":168,"detail_path":169},"S2 forward 1 CB 化 — replay -12〜13% \u002F busy 69 → 80% (default flip)","stable","positive","experiment",[91,144],3,[146,13,147,148,149,150,151,152,153,154,155,156],"1x-roadmap-v2","forward-chained","command-buffer","hierarchical-scan","indirect-dispatch","radix-sort","gpu-busy","sync-tax","bit-exact","lego","unified-memory","2026-08 1× 工程表 v2 — AC 復帰後 計測 queue #2 (S2 gate)",[159,160,161,5,162,163],"s2-12500-noprof-r1","s2-12500-noprof-r2","s2-12500-noprof-r3","s2gate-base-12500-r2","s2gate-base-12500-r3","12.5k **同一 session 交互 A\u002FB** n=3 mean: S2 **36.167 dB** (36.154 \u002F 36.192 \u002F 36.155) vs default **36.160 dB** (36.107 \u002F 36.167 \u002F 36.205) = **+0.007 dB** (guard ±0.1 内、n=3 mean 判定 — n=1 判定なし)。S2 は prefix scan 部分こそ bit-exact だが end-to-end では既存の atomic 順序非決定性を継承するため、この guard は実質的な検査として機能している (default arm 自身の run 間振れ幅が ±0.05 dB ある)","replay bench (σ ≤1.5% の clean block、ABBA 交互 2 round): final regime **17.833 → 15.637 ms\u002Fiter = -12.3%**、iter5000 regime **16.600 → 14.395 = -13.3%** (有意閾値 max(2σ,1%) = 1.0〜1.8%)。頑健性確認の min-to-min 推定でも -10.6% \u002F -13.6%。12.5k full run **同一 session 交互 A\u002FB n=3 mean: 208.26 → 187.65s = -9.9%** (training elapsed では 205.10 → 184.61s = -10.0%)。参考値として counter session 当日 baseline 216.12s 比では -13.2%","high","s2-adopted-default-flip-chained-forward-and-hierarchical-scan","1× 工程表 v2 の並列性能軸で\u003Cstrong>本命に格上げ\u003C\u002Fstrong>されていた S2 を gate し、採用した。W2 が backward\u002Floss chain を 1 CB に畳んだのに対し S2 は forward 側を畳む — radix の per-pass CPU prefix scan を hierarchical GPU scan (bit-exact な整数 prefix sum) に、pair_count の host readback を indirect dispatch に置き換え、forward 全段を \u003Cstrong>1 CB \u002F 1 encoder \u002F 末尾 1 wait\u003C\u002Fstrong> に連結した。replay \u003Cstrong>final -12.3% \u002F iter5000 -13.3%\u003C\u002Fstrong> (閾値 1.0〜1.8% の 8〜13 倍)、12.5k full run は\u003Cstrong>同一 session 交互 A\u002FB (ABBAAB) n=3 で 208.26 → 187.65s = -9.9%\u003C\u002Fstrong>。\u003Cstrong>counter session が積み残した「busy 68.9%」は 79.8% まで回復\u003C\u002Fstrong>し、sync-tax は 5.21 → 2.86 ms\u002Fiter (-45%)。roadmap が注目トレードに挙げた「dispatch 26 → ~60 の overhead」は \u003Cstrong>busy ms\u002Fiter +0.20 = 回収額の 1\u002F11〜1\u002F24\u003C\u002Fstrong> と定量的にケリがつき、follow-up (radix reduce の histogram fold) は\u003Cstrong>総額 -1.1% 未満と判明したため S3 の後ろに defer\u003C\u002Fstrong>。\u003Cstrong>full run の Δ (-9.9%) が replay の Δ (-12.3%) を下回る一方、iteration 別に見ると -24.7% (iter1000) → -10.0% (iter12500) と単調に縮む\u003C\u002Fstrong> — S2 が削るのが\u003Cstrong>splat 数に依らない固定の per-iter host コスト\u003C\u002Fstrong>であることの直接証拠で、W1\u002FW2 (GPU 仕事量に比例する施策) とは pass-through の性質が異なる。msplat 同日等価 gap は \u003Cstrong>1.273× → 1.105×\u003C\u002Fstrong>。累計 (数学的同値の施策のみ) 766.07 → 187.65s = \u003Cstrong>-75.5%\u003C\u002Fstrong>。","\u002Ffindings\u002Fp2-s2-forward-chained\u002F",1790227325618]