Rules Index
The page to open at 11pm. Each rule links back to the derivation that earned it. If you can rebuild the argument from the rule alone, you're done; if not, follow the link.
I. The Method
- Ratio triage: sort next questions by the spread between their possible answers. >10×: ask now. <2×: it's a detail.
- The floor test: when a measurement beats your theoretical floor, the work didn't happen.
- Match the instrument to the ratio: 1000× apart, wall clock. 1.5× apart, counters.
II. Durability
- Test the failure you claim to survive: a crash test that can't reach the layer your data lives in has proven nothing about that layer.
- Buy durability at boundaries, not by the record: fsync cost is dominated by the round trip, not the bytes. Pay it once per boundary, never once per write.
- fsync failure is not retryable: once fsync errors, the page behind it is already gone. Recover from an independent durable source, don't retry the same call.
- Let the barrier set its own batch size: close the batch when the in-flight fsync returns, not when a counter hits a constant.
- Checksum every record; seed the register nonzero: torn writes pass structural checks by accident. Only arithmetic over the content finds where the truth stops.
III. Accelerators
- Check arithmetic intensity before adding FLOPs: below the ridge point, more compute buys nothing. The wait is on bytes, not operations.
- Size your batch from the KV budget, not a guess: before blaming scheduling for a batch ceiling, check bytes-per-token × context length × concurrency against free memory.
IV. Building the Answer
- Release the slot when the sequence ends, not when the batch does: schedule per forward pass, not per request. A finished sequence leaves on the step it finishes; a waiting one takes its place.
- Page the cache; reserve for the token you have: when a per-client allocation grows unpredictably toward a large ceiling, allocate fixed-size blocks behind an indirection table.
- A workload that misses its own roofline floor is not yet bound by what you think: when a memory-bound workload takes longer than bytes ÷ bandwidth, the extra time is on the host. Count launches before optimizing kernels.
- Below the ridge, spend compute on work that might be wasted: idle compute does not accrue. Far under the ridge point, speculative work is free even when most of it is discarded.