docs(blog): three bits, each one necessary - CLK_PERF2 on silicon

apps/website/public/term/index.html

@@ -44,7 +44,7 @@
 <main>
 <div class="top"><a class="brand" href="../"><img src="../favicon.svg" alt="">Trinity S³AI</a></div>
 <h1>Recordings</h1>
-<p class="lede">Terminal sessions recorded from real commands: the output is what the commands printed. 30 so far.</p>
+<p class="lede">Terminal sessions recorded from real commands: the output is what the commands printed. 32 so far.</p>
 <div class="grid">
 <a href="tri-x7-refs/"><img src="tri-x7-refs/card.png" alt="" loading="lazy"><div><b>tri x7-part · x7-refs · x7-bench: the references the bitstream path is checked on</b><small>2026-10-04 04:52 UTC · 7.3 s real</small></div></a>
 <a href="tri-fpga-tools/"><img src="tri-fpga-tools/card.png" alt="" loading="lazy"><div><b>tri fpga-tools · 14 bench tools test themselves</b><small>2026-10-04 04:52 UTC · 5.8 s real</small></div></a>
@@ -54,6 +54,8 @@ <h1>Recordings</h1>
 <a href="tri-fpga-batch/"><img src="tri-fpga-batch/card.png" alt="" loading="lazy"><div><b>tri fpga-batch-rehearsal · the batched wire protocol, rehearsed off-board</b><small>2026-10-04 04:52 UTC · 4.7 s real</small></div></a>
 <a href="tri-x7-mutate/"><img src="tri-x7-mutate/card.png" alt="" loading="lazy"><div><b>tri x7-mutate · plant a bug, the tests must catch it</b><small>2026-10-04 04:48 UTC · 81.6 s real</small></div></a>
 <a href="tri-x7-audit/"><img src="tri-x7-audit/card.png" alt="" loading="lazy"><div><b>tri x7-audit · the whole bitstream path, re-checked</b><small>2026-10-04 03:38 UTC · 208.3 s real</small></div></a>
+<a href="perf2-loop/"><img src="perf2-loop/card.png" alt="" loading="lazy"><div><b>Place and route to a loaded bitstream, timed</b><small>2026-10-03 19:54 UTC · 22.6 s real</small></div></a>
+<a href="perf2-knockouts/"><img src="perf2-knockouts/card.png" alt="" loading="lazy"><div><b>Three PERF2 bits, and one knockout bitstream per bit</b><small>2026-10-03 19:53 UTC · 26.2 s real</small></div></a>
 <a href="tri-x7-fasm/"><img src="tri-x7-fasm/card.png" alt="" loading="lazy"><div><b>tri x7-fasm · a bitstream assembled without Vivado</b><small>2026-10-03 19:49 UTC · 21.7 s real</small></div></a>
 <a href="tri-fpga-wire/"><img src="tri-fpga-wire/card.png" alt="" loading="lazy"><div><b>tri fpga-wire · the baud rate actually on the wire</b><small>2026-10-03 19:49 UTC · 6.5 s real</small></div></a>
 <a href="tri-fpga-rgmii/"><img src="tri-fpga-rgmii/card.png" alt="" loading="lazy"><div><b>tri fpga-txhold · RGMII margins from nextpnr&#39;s own SDF</b><small>2026-10-03 19:49 UTC · 4.7 s real</small></div></a>

apps/website/public/term/perf2-knockouts/index.html

@@ -0,0 +1,95 @@
+<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<title>Three PERF2 bits, and one knockout bitstream per bit · Trinity S³AI</title>
+<meta name="description" content="The A/B bitstreams differ in three bits. Each knockout clears one: 3 bytes from the working .bit.">
+<link rel="canonical" href="https://t27.ai/term/perf2-knockouts/">
+<link rel="icon" href="../../favicon.svg" type="image/svg+xml">
+<meta property="og:type" content="article">
+<meta property="og:site_name" content="Trinity S³AI">
+<meta property="og:title" content="Three PERF2 bits, and one knockout bitstream per bit">
+<meta property="og:description" content="The A/B bitstreams differ in three bits. Each knockout clears one: 3 bytes from the working .bit.">
+<meta property="og:url" content="https://t27.ai/term/perf2-knockouts/">
+<meta property="og:image" content="https://t27.ai/term/perf2-knockouts/card.png">
+<meta property="og:image:width" content="1200">
+<meta property="og:image:height" content="630">
+<meta property="og:image:alt" content="Three PERF2 bits, and one knockout bitstream per bit: the terminal session it shows">
+<meta name="twitter:card" content="summary_large_image">
+<meta name="twitter:title" content="Three PERF2 bits, and one knockout bitstream per bit">
+<meta name="twitter:description" content="The A/B bitstreams differ in three bits. Each knockout clears one: 3 bytes from the working .bit.">
+<meta name="twitter:image" content="https://t27.ai/term/perf2-knockouts/card.png">
+<meta name="twitter:image:alt" content="Three PERF2 bits, and one knockout bitstream per bit: the terminal session it shows">
+<style>@font-face{font-family:Outfit;src:url(../../fonts/outfit-latin.woff2) format('woff2');font-weight:100 900;font-display:swap}
+*{box-sizing:border-box}html,body{margin:0;background:#000;color:#ebebeb}
+body{font:16px/1.6 Outfit,system-ui,sans-serif;background-image:linear-gradient(rgba(255,255,255,.025) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.025) 1px,transparent 1px);background-size:40px 40px}
+main{max-width:980px;margin:0 auto;padding:28px 20px 64px}
+a{color:#00ff88}a:hover{color:#fff}
+.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-weight:700;font-size:20px}
+.brand img{width:30px;height:30px}
+.top{display:flex;justify-content:space-between;align-items:center;margin-bottom:28px}
+.top .all{color:#888;font-size:14px;text-decoration:none}.top .all:hover{color:#00ff88}
+h1{font-size:clamp(26px,4.4vw,42px);line-height:1.15;margin:0 0 10px;color:#fff}
+.lede{color:#888;margin:0 0 22px;font-size:18px}
+.facts{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0}
+.facts span{border:1px solid rgba(255,255,255,.08);border-radius:999px;padding:3px 12px;font-size:13px;color:#bbb}
+.facts b{color:#ffd700;font-weight:600}
+.cmds{font:13px/1.5 'JetBrains Mono',Menlo,monospace;background:#0a0a0a;border:1px solid rgba(255,255,255,.08);border-radius:10px;padding:12px 16px;margin:18px 0;white-space:pre-wrap;overflow-wrap:anywhere}
+.cmds i{color:#ffd700;font-style:normal}
+.honest{color:#888;font-size:14px;border-left:2px solid #00ff88;padding-left:12px}
+.links{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
+.links a{border:1px solid rgba(255,255,255,.16);border-radius:8px;padding:6px 14px;text-decoration:none;font-size:14px}
+.links a.x{background:#00ff88;color:#000;border-color:#00ff88;font-weight:600}
+.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px}
+.grid a{display:block;border:1px solid rgba(255,255,255,.08);border-radius:12px;overflow:hidden;text-decoration:none;color:#ebebeb;background:#050505}
+.grid a:hover{border-color:#00ff88}.grid img{width:100%;display:block;aspect-ratio:1200/630}
+.grid div{padding:10px 14px}.grid b{display:block;color:#fff}.grid small{color:#888}</style>
+</head>
+<body>
+<main>
+<div class="top"><a class="brand" href="../../"><img src="../../favicon.svg" alt="">Trinity S³AI</a><a class="all" href="../">All recordings →</a></div>
+<h1>Three PERF2 bits, and one knockout bitstream per bit</h1>
+<p class="lede">The A/B bitstreams differ in three bits. Each knockout clears one: 3 bytes from the working .bit.</p>
+<div id="player"><noscript><figure style='margin:0 0 1.6em;border:1px solid rgba(255,255,255,.08);border-radius:12px;overflow:hidden;background:#000'><div style='padding:8px 12px;background:#0a0a0a;color:#888;font:12px system-ui;text-align:center;border-bottom:1px solid rgba(255,255,255,.08)'>Three PERF2 bits: which ones, and one knockout bitstream per bit</div><pre style='margin:0;padding:14px 16px;color:#ebebeb;background:#000;font:12px/1.25 Menlo,monospace;overflow-x:auto'><span style='color:#ebebeb'>  28_994   0 -> 1   rows using it: c030ed6 CLK_PERF2.{CLKOUT2,CLKOUT3}                                  </span>
+<span style='color:#ebebeb'>                                   master  none                                                         </span>
+<span style='color:#ebebeb'>  29_1022  0 -> 1   rows using it: c030ed6 CLK_PERF2.{CLKFBOUT,CLKOUT0,CLKOUT1,CLKOUT2,CLKOUT3}         </span>
+<span style='color:#ebebeb'>                                   master  none                                                         </span>
+<span style='color:#ebebeb'>HCLK_CMT_X8Y234                                                                                         </span>
+<span style='color:#ebebeb'>  28_180   0 -> 1   rows using it: c030ed6 PERFCLK2.{MUXED2,MUXED3}                                     </span>
+<span style='color:#ebebeb'>                                   master  none                                                         </span>
+<span style='color:#ffd700'>board $ </span><span style='color:#ebebeb'>python3 perf2.py knockout bufr-new.frames --out rec                                             </span>
+
+<span style='color:#ebebeb'>== CMT_TOP_R_LOWER_B_X8Y217 28_994: frame 0x0002009C word 31 bit 2, 1 -> 0                              </span>
+<span style='color:#ebebeb'>  rec/ko-28_994.frames == ko-28_994.frames (the file flashed on 2026-10-04)                             </span>
+<span style='color:#ebebeb'>$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_</span>
+<span style='color:#ebebeb'>file rec/ko-28_994.frames --output_file rec/ko-28_994.bit                                               </span>
+<span style='color:#ebebeb'>  rc=0  0.59 s                                                                                          </span>
+<span style='color:#ebebeb'>  past the sync word, rec/ko-28_994.bit differs from bufr-new.bit in 3 bytes                            </span>
+
+<span style='color:#ebebeb'>== CMT_TOP_R_LOWER_B_X8Y217 29_1022: frame 0x0002009D word 31 bit 30, 1 -> 0                            </span>
+<span style='color:#ebebeb'>  rec/ko-29_1022.frames == ko-29_1022.frames (the file flashed on 2026-10-04)                           </span>
+<span style='color:#ebebeb'>$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_</span>
+<span style='color:#ebebeb'>file rec/ko-29_1022.frames --output_file rec/ko-29_1022.bit                                             </span>
+<span style='color:#ebebeb'>  rc=0  0.90 s                                                                                          </span>
+<span style='color:#ebebeb'>  past the sync word, rec/ko-29_1022.bit differs from bufr-new.bit in 3 bytes                           </span>
+
+<span style='color:#ebebeb'>== HCLK_CMT_X8Y234 28_180: frame 0x0002009C word 50 bit 20, 1 -> 0                                      </span>
+<span style='color:#ebebeb'>  rec/ko-28_180.frames == ko-28_180.frames (the file flashed on 2026-10-04)                             </span>
+<span style='color:#ebebeb'>$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_</span>
+<span style='color:#ebebeb'>file rec/ko-28_180.frames --output_file rec/ko-28_180.bit                                               </span>
+<span style='color:#ebebeb'>  rc=0  0.55 s                                                                                          </span>
+<span style='color:#ebebeb'>  past the sync word, rec/ko-28_180.bit differs from bufr-new.bit in 3 bytes                            </span>
+<span style='color:#ffd700'>board $ </span><span style='color:#ebebeb'>                                                                                                </span></pre></figure></noscript></div>
+<div class="facts"><span>recorded <b>2026-10-03 19:53 UTC</b></span><span>real <b>26.2 s</b></span><span>shown <b>15.9 s</b></span><span>exit codes <b>0 0</b></span></div>
+<div class="cmds"><i>$</i> python3 perf2.py diff bufr-old.frames bufr-new.frames
+<i>$</i> python3 perf2.py knockout bufr-new.frames --out rec</div>
+<p class="honest">Staged: the prompt and the typing. Real: every byte the commands printed, at the time they printed it. Any silence longer than 2 s is shown for 2 s, and the title bar says so while it happens. Edited: home directory shown as ~.</p>
+<div class="links"><a href="https://t27.ai/#/blog/three-bits-each-necessary">Read the post</a><a href="session.gif">GIF</a><a href="card.png">Preview card</a></div>
+</main>
+<script type="module">
+import { mount } from '../player.js'
+mount(document.getElementById('player'), { src: 'session.cast', share: "https://t27.ai/term/perf2-knockouts/", title: "Three PERF2 bits: which ones, and one knockout bitstream per bit" })
+</script>
+</body>
+</html>

apps/website/public/term/perf2-knockouts/meta.json

@@ -0,0 +1,23 @@
+{
+  "id": "perf2-knockouts",
+  "title": "Three PERF2 bits, and one knockout bitstream per bit",
+  "desc": "The A/B bitstreams differ in three bits. Each knockout clears one: 3 bytes from the working .bit.",
+  "url": "https://t27.ai/term/perf2-knockouts/",
+  "gif": "https://t27.ai/term/perf2-knockouts/session.gif",
+  "post": "https://t27.ai/#/blog/three-bits-each-necessary",
+  "recorded": "2026-10-03 19:53 UTC",
+  "real_s": 26.2,
+  "shown_s": 15.9,
+  "commands": [
+    "python3 perf2.py diff bufr-old.frames bufr-new.frames",
+    "python3 perf2.py knockout bufr-new.frames --out rec"
+  ],
+  "exit_codes": [
+    "0",
+    "0"
+  ],
+  "redacted": [
+    "home directory shown as ~"
+  ],
+  "published": "2026-10-03"
+}

apps/website/public/term/perf2-knockouts/session.cast

@@ -0,0 +1,131 @@
+{"version": 2, "width": 104, "height": 30, "timestamp": 1791057239, "title": "Three PERF2 bits: which ones, and one knockout bitstream per bit", "commands": ["python3 perf2.py diff bufr-old.frames bufr-new.frames", "python3 perf2.py knockout bufr-new.frames --out rec"], "redacted": ["home directory shown as ~"]}
+[0.0001, "o", "\u001b[38;2;255;215;0mboard $ \u001b[0m"]
+[0.4101, "o", "p"]
+[0.4552, "o", "y"]
+[0.4935, "o", "t"]
+[0.5337, "o", "h"]
+[0.5705, "o", "o"]
+[0.6059, "o", "n"]
+[0.6437, "o", "3"]
+[0.6889, "o", " "]
+[0.7285, "o", "p"]
+[0.7696, "o", "e"]
+[0.8108, "o", "r"]
+[0.8471, "o", "f"]
+[0.8926, "o", "2"]
+[0.9305, "o", "."]
+[0.9696, "o", "p"]
+[1.0097, "o", "y"]
+[1.0466, "o", " "]
+[1.09, "o", "d"]
+[1.1359, "o", "i"]
+[1.1718, "o", "f"]
+[1.2162, "o", "f"]
+[1.2612, "o", " "]
+[1.3021, "o", "b"]
+[1.3442, "o", "u"]
+[1.3887, "o", "f"]
+[1.4239, "o", "r"]
+[1.4683, "o", "-"]
+[1.5137, "o", "o"]
+[1.5536, "o", "l"]
+[1.5972, "o", "d"]
+[1.6371, "o", "."]
+[1.686, "o", "f"]
+[1.7268, "o", "r"]
+[1.7702, "o", "a"]
+[1.8153, "o", "m"]
+[1.8568, "o", "e"]
+[1.8963, "o", "s"]
+[1.9354, "o", " "]
+[1.9806, "o", "b"]
+[2.0263, "o", "u"]
+[2.0682, "o", "f"]
+[2.1071, "o", "r"]
+[2.1487, "o", "-"]
+[2.1885, "o", "n"]
+[2.2394, "o", "e"]
+[2.2784, "o", "w"]
+[2.3236, "o", "."]
+[2.3596, "o", "f"]
+[2.4071, "o", "r"]
+[2.4582, "o", "a"]
+[2.4942, "o", "m"]
+[2.5393, "o", "e"]
+[2.5812, "o", "s"]
+[2.9287, "o", "\r\n"]
+[10.3484, "o", "bufr-old.frames -> bufr-new.frames: 3 bit(s) differ, frame ECC aside\r\n"]
+[10.3781, "o", "CMT_TOP_R_LOWER_B_X8Y217\r\n"]
+[10.3937, "o", "  28_994   0 -> 1   rows using it: c030ed6 CLK_PERF2.{CLKOUT2,CLKOUT3}\r\n                                   master  none\r\n"]
+[10.3944, "o", "  29_1022  0 -> 1   rows using it: c030ed6 CLK_PERF2.{CLKFBOUT,CLKOUT0,CLKOUT1,CLKOUT2,CLKOUT3}\r\n                                   master  none\r\nHCLK_CMT_X8Y234\r\n"]
+[10.4074, "o", "  28_180   0 -> 1   rows using it: c030ed6 PERFCLK2.{MUXED2,MUXED3}\r\n                                   master  none\r\n"]
+[10.5448, "x", "0"]
+[11.5525, "o", "\u001b[38;2;255;215;0mboard $ \u001b[0m"]
+[12.0129, "o", "p"]
+[12.0829, "o", "y"]
+[12.1199, "o", "t"]
+[12.168, "o", "h"]
+[12.2249, "o", "o"]
+[12.2633, "o", "n"]
+[12.3251, "o", "3"]
+[12.3746, "o", " "]
+[12.4185, "o", "p"]
+[12.4633, "o", "e"]
+[12.5089, "o", "r"]
+[12.5579, "o", "f"]
+[12.5933, "o", "2"]
+[12.6418, "o", "."]
+[12.6884, "o", "p"]
+[12.7322, "o", "y"]
+[12.7918, "o", " "]
+[12.8343, "o", "k"]
+[12.8755, "o", "n"]
+[12.9257, "o", "o"]
+[12.9724, "o", "c"]
+[13.009, "o", "k"]
+[13.0481, "o", "o"]
+[13.0835, "o", "u"]
+[13.1302, "o", "t"]
+[13.1687, "o", " "]
+[13.208, "o", "b"]
+[13.2464, "o", "u"]
+[13.2831, "o", "f"]
+[13.3195, "o", "r"]
+[13.3663, "o", "-"]
+[13.4064, "o", "n"]
+[13.4442, "o", "e"]
+[13.4908, "o", "w"]
+[13.5373, "o", "."]
+[13.5741, "o", "f"]
+[13.6169, "o", "r"]
+[13.6582, "o", "a"]
+[13.7006, "o", "m"]
+[13.7433, "o", "e"]
+[13.7841, "o", "s"]
+[13.8276, "o", " "]
+[13.9087, "o", "-"]
+[13.9597, "o", "-"]
+[14.0158, "o", "o"]
+[14.0726, "o", "u"]
+[14.1191, "o", "t"]
+[14.1685, "o", " "]
+[14.2135, "o", "r"]
+[14.2697, "o", "e"]
+[14.3138, "o", "c"]
+[14.6649, "o", "\r\n"]
+[21.5975, "o", "\r\n== CMT_TOP_R_LOWER_B_X8Y217 28_994: frame 0x0002009C word 31 bit 2, 1 -> 0\r\n"]
+[21.6137, "o", "  rec/ko-28_994.frames == ko-28_994.frames (the file flashed on 2026-10-04)\r\n$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_file rec/ko-28_994.frames --output_file rec/ko-28_994.bit\r\n"]
+[22.2006, "o", "  rc=0  0.59 s\r\n"]
+[22.7853, "o", "  past the sync word, rec/ko-28_994.bit differs from bufr-new.bit in 3 bytes\r\n"]
+[22.8778, "o", "\r\n== CMT_TOP_R_LOWER_B_X8Y217 29_1022: frame 0x0002009D word 31 bit 30, 1 -> 0\r\n"]
+[22.8885, "o", "  rec/ko-29_1022.frames == ko-29_1022.frames (the file flashed on 2026-10-04)\r\n"]
+[22.8885, "o", "$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_file rec/ko-29_1022.frames --output_file rec/ko-29_1022.bit\r\n"]
+[23.7913, "o", "  rc=0  0.90 s\r\n"]
+[24.1817, "o", "  past the sync word, rec/ko-29_1022.bit differs from bufr-new.bit in 3 bytes\r\n"]
+[24.2635, "o", "\r\n== HCLK_CMT_X8Y234 28_180: frame 0x0002009C word 50 bit 20, 1 -> 0"]
+[24.2643, "o", "\r\n"]
+[24.28, "o", "  rec/ko-28_180.frames == ko-28_180.frames (the file flashed on 2026-10-04)\r\n$ xc7frames2bit --part_file db-new/artix7/xc7a200tfbg484-2/part.yaml --part_name xc7a200tfbg484-2 --frm_file rec/ko-28_180.frames --output_file rec/ko-28_180.bit\r\n"]
+[24.8309, "o", "  rc=0  0.55 s\r\n"]
+[25.1509, "o", "  past the sync word, rec/ko-28_180.bit differs from bufr-new.bit in 3 bytes\r\n"]
+[25.2216, "x", "0"]
+[26.2266, "o", "\u001b[38;2;255;215;0mboard $ \u001b[0m"]