the bench
where the gates land · rows marked predicted or computed are roofline-derived · cpu-interpret and simulated rows are verified off-chip · hardware rows replace both
Every number, with provenance.
Nothing quantitative appears on this site outside an instrument, and every value states what it is. Each record carries chip, dtype, shapes, date, and the lab that produced it; gate verdicts on the chapter pages resolve to rows here.
records
10
10
The record
| id | kernel | metric | value | baseline | chip | dtype | shapes | date |
|---|---|---|---|---|---|---|---|---|
| P-001 | matmul NxNxN | predicted floor (roofline) | 697.7 µs | chip constants | v5e (predicted) | bf16 | 4096³ | 2026-07-26 |
| P-002 | matmul skinny 8xNxN | predicted floor (roofline) | 41.1 µs | chip constants | v5e (predicted) | bf16 | 8x4096x4096 | 2026-07-26 |
| P-003 | elementwise add | predicted floor (roofline) | 122.8 µs | chip constants | v5e (predicted) | bf16 | 4096² | 2026-07-26 |
| P-004 | softmax rows | predicted floor (roofline) | 81.8 µs | chip constants | v5e (predicted) | bf16 | 4096² | 2026-07-26 |
| P-005 | naive attention spill | computed HBM round-trip | 268 MB | score matrix size | any (computed) | bf16 | seq 8192 | 2026-07-26 |
| C-001 | flash forward (lab 3.2) | max err vs reference | ≤ 1e-4 | jax.nn.softmax @ v | cpu interpret | f32 | 512x1024x64 | 2026-07-26 |
| C-002 | attention custom_vjp grads (lab 3.3) | max err vs jax.grad | ≤ 1e-5 | autodiff of reference | cpu interpret | f32 | 128x256x64 | 2026-07-26 |
| C-003 | causal flash, blocks skipped (lab 3.4) | max err vs masked reference | ≤ 1e-4 | dense masked attention | cpu interpret | f32 | 512x512x64 | 2026-07-26 |
| C-004 | ring all-gather (lab 4.1) | match vs lax.all_gather | exact | collective | 8 simulated devices | f32 | 8 shards x 4x128 | 2026-07-26 |
| C-005 | ring attention (lab 4.2) | max err vs full attention | ≤ 1e-5 | single-device reference | 8 simulated devices | f32 | 128x256x64 sharded | 2026-07-26 |
compare
Your chip against the record
Ran a lab? Paste the results blob its final cell printed. Parsed in your browser; nothing you paste is sent anywhere.
waiting for a results blob ·
Parsed in your browser. Nothing you paste here is sent anywhere.