The owner's decision, applied: a vendor energy counter (RAPL, NVML, IOReport)
is a real reading, and what separates one such reading from another is
provenance, not accuracy. This crate gave RAPL and NVML `HwShunt` and gave the
IOReport counter `ModelBased`, on the reasoning that Apple's Energy Model is a
vendor model. That reasoning grades accuracy. What the counter could not
establish was provenance: on macOS 27.0.1 its CPU rails are frozen for an
unprivileged reader, and that is now caught by the liveness probe. A counter
that has passed it is as much a reading as RAPL is.
The grade. `AppleIoReportCounter` declares `HwShunt`, and stamps it on every
reading through one constant, `READING_GRADE`, shared by `provenance()` and
`read()`. It earns the grade by being live: the counter exists to read only
where `admits()` let it through (CPU rail `Live`), and a declined counter
produces no reading to carry any grade, so a frozen host still meters through
the load-average estimator at `Estimator`.
The rule, written once and shared (jouleclaw SPEC §1.3, §9.4; JCR-1 §2.3;
the crate docs; vendor-energy PROTOCOL/README): a vendor counter's reading MAY
be graded as a hardware reading only while the counter is demonstrably live for
the domain the figure claims; the implementation MUST have observed the counter
covering that domain advance under load (for IOReport: the CPU rail itself, in
at least 5 intervals, 4 of every 5, over at least 300 ms while the probing
thread burns CPU). A counter present but not live MUST NOT produce a
hardware-graded figure; the implementation falls back to its estimator or
reports the work unmetered, and SHOULD record why. A figure MUST NOT claim
coverage of a domain its counter does not read; where the format has a coverage
field, such a figure is Partial.
No partial reading from the GPU rail. Where the CPU rail is frozen but `GPU
Energy` still advances (the M5 Max), the counter stays declined. The GPU rail
is machine-wide: every GPU client on the host moves it, display compositing
included, with nothing of the metered work running. It does not cover part of
the work; it covers other work, so no coverage field makes it honest. The
rationale is in the module docs and SPEC §1.3.
Docs and data that said otherwise:
- SPEC §1.3 table and floors, §9.4; JCR-1 §2.3 and the crate README (toy
vectors become measurements only off counters that were live).
- JCR-1 vector 6's description said "measured on Apple IOReport". Its joules
are toy values like every vector's. Only the `description` changed; it sits
outside the signed core, which `verify.py` builds from `receipt` alone. Both
verifiers pass 10/10 after the edit: `verify.py` (cbor2 6.1.4, cryptography
50.0.2, exit 0) and the independent `verify.go` (exit 0). `git diff` of the
file is that one line; a field-by-field JSON diff finds only (6,
description). The conformance README's slot 6 line follows.
- vendor-energy conformance: README row 27 names `AppleIoReportCounter` and the
`HwShunt` grade, with the liveness condition a filled fixture must meet;
`apple-silicon-ioreport.json` is an unsigned, empty stub (`signed_by` null,
every workload not run, no hash of it anywhere), so its `impl` and
`provenance` are corrected in place.
- MEASURED_ENERGY.md: a dated note that the 74.1 J / 25.5 W row was committed
2026-06-12, predates macOS 27, and recorded neither chip nor OS. The "reads
CPU/GPU/ANE/DRAM with no sudo" claim is replaced by what macOS 27.0.1 does:
the counter opens without sudo, but the CPU rails are frozen (all 645 rails
on the M3 Ultra), so those hosts are estimated.
- local-index / rerank tier SHOULDs, the CLI's `meter` help, meter.rs,
apple.rs, energy_probe, Cargo feature comments, harness-econ docs.
- l3-jouleclaw README: it claimed `HwShunt` on RAPL/NVML hosts, but the
binding builds jouleclaw-energy with `ioreport` only, so off Apple Silicon
the receipt is the token estimate. It now says what happens on each host.
- mesh-schema's `HwShunt` definition includes vendor counters subject to
liveness; mesh-meter, the mesh README and mesh-engine-gguf no longer say
real silicon alone yields `HwShunt`.
- The Live-branch assertions in mesh-meter, l3-jouleclaw and jouledesk-github
expected `ModelBased` for IOReport; they expect `HwShunt`. jouledesk-github's
fixtures that paired `apple-ioreport` with `ModelBased` now pair it with
`HwShunt`, and keep a `ModelBased` case under a neutral meter name.
Tests. `a_live_counters_readings_are_graded_as_hardware_readings` builds a
counter on `Live` directly. That opens the real all-channel subscription, which
opens here even though the gate declines this host. It reads it twice and
asserts each reading is `HwShunt` over `SocTotal`. On this M5 Max (macOS 27.0.1):
"an admitted IOReport counter: opens=true, 2 readings, each graded HwShunt",
so the read path is covered on a frozen host. With `--features "ioreport
rapl"`, `a_live_ioreport_reading_has_the_grade_of_a_rapl_reading` compares the
grade with `RaplCounter`'s own. The used/declined tests assert `HwShunt` in
their live branch. This host still takes the declined branch: "ioreport
declined (CpuRailFrozen): 154 ms of CPU work metered by `apple-silicon` as
6200000 µJ, provenance estimator".
Run on this M5 Max: jouleclaw-energy 24+1+1 (default), 76 lib + 1 + 1
(`ioreport`), 79 lib (`ioreport rapl`); jouleclaw-jcr1 50; harness-econ 14;
local-index 41; rerank 37; cli 10; mesh-meter (`hw-meter-apple`) 10;
mesh-engine-gguf 1; l3-jouleclaw 2 + 4 (2 ignored, need a model);
jouledesk-github 12. All pass.
Falsified, each mutant restored with `git checkout` and the tree confirmed clean:
- `READING_GRADE` set back to `ModelBased`: the new test fails at the
declared grade (left: ModelBased, right: HwShunt), 75 passed / 1 failed.
- Only `read()`'s stamp set back to `ModelBased` (the declared grade left at
`HwShunt`): the new test fails on the reading itself, "a live counter's
reading is not graded as a hardware reading" (ModelBased, SocTotal) vs
(HwShunt, SocTotal), 75 / 1. The read path is what the test pins.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
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