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[superseded by #181] energy tests: assert what the probe reports, not what the host's scheduler allows #178

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dcharlot wants to merge 3 commits from fix/energy-test-load-sensitivity into main
pull from: fix/energy-test-load-sensitivity
merge into: Transaction-Science:main
Conversation 0 Commits 3 Files changed 9 +512 -144
9 changed files with 512 additions and 144 deletions
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242
eoc/eoc-rs/crates/eoc-meter/src/lib.rs
View file

@ -361,9 +361,9 @@ mod rail_liveness {
/// could be taken; each one taken is handed to the rule with the wall
/// clock `now` read as it returns. [`probe_with`] runs it with the
/// sampler, tick and wall clock it is given, and records each sample call.
pub(crate) fn watch(
pub(crate) fn watch<T>(
sample: impl FnMut() -> Option<Vec<(String, i64)>>,
tick: impl FnMut(),
tick: impl FnMut() -> T,
now: impl Fn() -> Duration,
budget: Duration,
) -> RailWatch {
@ -372,10 +372,10 @@ mod rail_liveness {
/// [`watch`], folding samples into the watch `w` it is given (so a
/// single vendor counter's probe watches every channel).
pub(crate) fn watch_from(
pub(crate) fn watch_from<T>(
mut w: RailWatch,
mut sample: impl FnMut() -> Option<Vec<(String, i64)>>,
mut tick: impl FnMut(),
mut tick: impl FnMut() -> T,
now: impl Fn() -> Duration,
budget: Duration,
) -> RailWatch {
@ -401,20 +401,40 @@ mod rail_liveness {
/// clock stands still, and the tick simply takes longer. Only the wall cap
/// can cut a tick short, on a host that gives this thread less than
/// `want / wall_cap` of a core (5% for the probe's 25 ms in 500 ms).
/// What one tick of the CPU-burning spin did.
///
/// `spins` is the point of this type. A tick ends on either of two
/// conditions — the CPU target, or the wall cap — and from the outside the
/// two outcomes that matter are indistinguishable by time alone: a spin the
/// host starved into the cap and a tick that simply *slept* both show a
/// full wall span against little CPU. The only honest separator is whether
/// the spin loop ran at all, which only the spin can report. A test that
/// infers it from a CPU threshold is choosing a number the host can defeat
/// in either direction.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) struct TickOutcome {
/// The thread CPU the spin saw itself burn.
pub(crate) cpu: Duration,
/// Turns of the spin loop. Zero means the tick never span.
pub(crate) spins: u64,
}
pub(crate) fn spin_for_cpu(
thread_cpu: impl Fn() -> Duration,
wall: impl Fn() -> Duration,
want: Duration,
wall_cap: Duration,
) -> Duration {
) -> TickOutcome {
let (cpu0, wall0) = (thread_cpu(), wall());
let mut acc: u64 = 0;
let mut spins: u64 = 0;
loop {
let used = thread_cpu().saturating_sub(cpu0);
if used >= want || wall().saturating_sub(wall0) >= wall_cap {
std::hint::black_box(acc);
return used;
return TickOutcome { cpu: used, spins };
}
spins += 1;
for _ in 0..256 {
acc = std::hint::black_box(acc.wrapping_add(1));
}
@ -443,6 +463,16 @@ mod rail_liveness {
/// another process's all-channel sample can hold IOReport for hundreds
/// of milliseconds, and this call waits for it.
pub(crate) wall: Duration,
/// The wall clock just before and just after the call, absolute.
///
/// Recorded as a pair, like the CPU readings below, so the gap *between*
/// two calls is derivable in both clocks from the same source. A tick is
/// bounded by 25 ms of thread CPU **or** a 500 ms wall cap, so a test
/// holding only the CPU gap cannot tell a tick that burned its CPU from
/// one the host starved into the cap — see
/// `the_probe_burns_its_tick_of_thread_cpu_between_samples`.
pub(crate) wall_before: Duration,
pub(crate) wall_after: Duration,
/// The probing thread's CPU clock just before and just after the call.
pub(crate) cpu_before: Duration,
pub(crate) cpu_after: Duration,
@ -463,6 +493,8 @@ mod rail_liveness {
pub(crate) opened: bool,
/// Ticks run between samples.
pub(crate) ticks: u32,
/// What each of those ticks did, in order. `ticks` is its length.
pub(crate) tick_outcomes: Vec<TickOutcome>,
/// Every sample call, in order.
pub(crate) calls: Vec<SampleCall>,
/// The rule, folded over every sample that was taken.
@ -484,7 +516,7 @@ mod rail_liveness {
/// the rule in [`watch`] for `budget`, and records every sample call.
pub(crate) fn probe_with<S>(
open: impl FnOnce() -> Option<S>,
mut tick: impl FnMut(),
mut tick: impl FnMut() -> TickOutcome,
thread_cpu: impl Fn() -> Duration,
wall: impl Fn() -> Duration,
budget: Duration,
@ -493,9 +525,15 @@ mod rail_liveness {
S: FnMut() -> Option<Sample>,
{
let Some(mut sampler) = open() else {
return ProbeRun { opened: false, ticks: 0, calls: Vec::new(), watch: RailWatch::default() };
return ProbeRun {
opened: false,
ticks: 0,
tick_outcomes: Vec::new(),
calls: Vec::new(),
watch: RailWatch::default(),
};
};
let (mut calls, mut ticks) = (Vec::new(), 0u32);
let (mut calls, mut ticks, mut tick_outcomes) = (Vec::new(), 0u32, Vec::new());
let watch = watch(
|| {
let (cpu_before, started) = (thread_cpu(), wall());
@ -503,6 +541,8 @@ mod rail_liveness {
let (ended, cpu_after) = (wall(), thread_cpu());
calls.push(SampleCall {
wall: ended.saturating_sub(started),
wall_before: started,
wall_after: ended,
cpu_before,
cpu_after,
shape: sample.as_ref().map(|s| (s.channels, s.group_only)),
@ -512,12 +552,12 @@ mod rail_liveness {
},
|| {
ticks += 1;
tick();
tick_outcomes.push(tick());
},
&wall,
budget,
);
ProbeRun { opened: true, ticks, calls, watch }
ProbeRun { opened: true, ticks, tick_outcomes, calls, watch }
}
/// The status a probe verdict gives this host. No verdict — no
@ -551,10 +591,10 @@ mod rail_liveness {
/// over each part so the tests drive this very function with a scripted
/// counter, tick and clock; each rung's cached probe passes the real ones.
#[cfg_attr(not(any(target_os = "linux", target_os = "macos", feature = "cuda")), allow(dead_code))] // used by RAPL, NVML and the process counter
pub(crate) fn probe_counter<C>(
pub(crate) fn probe_counter<C, T>(
open: impl FnOnce() -> Option<C>,
mut sample: impl FnMut(&C) -> Option<Vec<(String, i64)>>,
tick: impl FnMut(),
tick: impl FnMut() -> T,
now: impl Fn() -> Duration,
budget: Duration,
) -> Option<RailWatch> {
@ -1131,6 +1171,9 @@ mod rail_liveness {
ticked.set(ticked.get() + 1);
wall.set(wall.get() + step);
cpu.set(cpu.get() + TICK);
// A scripted tick that reaches its CPU target: it reports a
// spin so a consumer can tell it apart from one that waited.
TickOutcome { cpu: TICK, spins: 1 }
},
|| cpu.get(),
|| wall.get(),
@ -1292,7 +1335,7 @@ mod rail_liveness {
want,
cap,
);
(used, cpu_reads.get())
(used.cpu, cpu_reads.get())
}
/// The tick spins until this thread's CPU clock has advanced by the
@ -1509,8 +1552,8 @@ mod clocks {
/// One tick of a CPU-burning probe: spin until this thread's CPU clock has
/// advanced [`PROBE_TICK`], or [`PROBE_TICK_WALL_CAP`] of wall time has
/// passed.
pub(crate) fn cpu_burn_tick() {
crate::rail_liveness::spin_for_cpu(thread_cpu_time, wall_now, PROBE_TICK, PROBE_TICK_WALL_CAP);
pub(crate) fn cpu_burn_tick() -> crate::rail_liveness::TickOutcome {
crate::rail_liveness::spin_for_cpu(thread_cpu_time, wall_now, PROBE_TICK, PROBE_TICK_WALL_CAP)
}
}
@ -1818,8 +1861,8 @@ mod macos_ioreport {
}
/// One tick of the probe: [`crate::clocks::cpu_burn_tick`].
fn probe_tick() {
crate::clocks::cpu_burn_tick();
fn probe_tick() -> crate::rail_liveness::TickOutcome {
crate::clocks::cpu_burn_tick()
}
/// How many times [`host_status`] — the probe behind the cached
@ -3089,19 +3132,41 @@ mod macos_ioreport {
}
}
/// The production probe burns CPU between samples, and exactly its tick
/// of it, pinned per tick on the probe's own records of this thread's
/// CPU clock (identified as such by the thread-clock test) so host load
/// cannot fail it: the CPU the thread consumed between the end of one
/// sample call and the start of the next must be at least half the
/// 25 ms tick (a probe that sleeps, or does nothing, between samples
/// burns ~0) and at most twice it (a slower cadence, e.g. a 100 ms tick,
/// burns more). And the tick CPU the probe recorded is checked against
/// the tests' own reading of the thread's CPU clock over the whole probe,
/// and every thread-clock reading the probe recorded must lie between the
/// tests' own readings of this thread's CPU clock just before and just
/// after it: the clock the production composition hands the probe is
/// this thread's CPU clock, not the wall clock or the process's.
/// The production probe burns CPU between samples rather than waiting or
/// skipping, pinned per tick.
///
/// This test used to require that each inter-sample gap carry at least
/// half the 25 ms tick of thread CPU, on the reasoning that a tick spins
/// on the *thread's* clock and so "host load cannot fail it". That
/// reasoning was wrong, and its own failure message said why: a tick also
/// stops at [`crate::clocks::PROBE_TICK_WALL_CAP`], so a host that gives
/// this thread a sliver of a core caps the tick with little CPU to show.
/// It failed on the macOS CI runner — which is the dev Mac, under other
/// work — exactly that way.
///
/// No CPU threshold can replace it, because the two outcomes that matter
/// are not separable by time: a spin the host starved into the cap and a
/// tick that simply *slept* both show a long wall span against little
/// CPU. Measured here, a sleeping tick's turns cost *more* thread CPU
/// than real ones (13.3-15.8 µs against 2.13-2.92 µs), because a blocking
/// body's context switch is charged to the thread — so even the direction
/// of a threshold is wrong.
///
/// So the tick reports what it did: [`rail_liveness::TickOutcome`] carries
/// the CPU it saw itself burn and how many turns of the spin loop it ran.
/// Per tick this test then requires that the loop ran at all (`spins > 0`
/// — a tick that never span did not burn CPU, at any load) and that the
/// tick stopped for one of its two stated reasons rather than early. The
/// gaps measured by the tests' own clocks bound it from above (a slower
/// cadence burns more) and keep CPU under wall.
///
/// What this does **not** establish: that the spin body is CPU-bound
/// rather than blocking. Nothing the probe reports separates those.
///
/// Also pinned here, unchanged: every thread-clock reading the probe
/// recorded lies between the tests' own readings around it, so the clock
/// the production composition hands the probe is this thread's CPU clock
/// and not the wall clock or the process's.
#[test]
fn the_probe_burns_its_tick_of_thread_cpu_between_samples() {
let own0 = own_thread_cpu();
@ -3127,38 +3192,99 @@ mod macos_ioreport {
assert!(run.calls.is_empty() && run.ticks == 0, "{run:?}");
return;
}
let ticks: Vec<Duration> =
run.calls.windows(2).map(|w| w[1].cpu_before.saturating_sub(w[0].cpu_after)).collect();
let recorded: Duration = ticks.iter().sum();
// Each inter-sample gap in the tests' own clocks: the CPU gap as
// before, and the wall gap beside it, from the same pair of calls.
// Both are needed, because a tick stops on EITHER the CPU target or
// the 500 ms wall cap.
let gaps: Vec<(Duration, Duration)> = run
.calls
.windows(2)
.map(|w| {
(
w[1].cpu_before.saturating_sub(w[0].cpu_after),
w[1].wall_before.saturating_sub(w[0].wall_after),
)
})
.collect();
let cpus: Vec<Duration> = gaps.iter().map(|(c, _)| *c).collect();
let recorded: Duration = cpus.iter().sum();
let capped = run.tick_outcomes.iter().filter(|t| t.cpu < TICK).count();
eprintln!(
"ioreport probe tick: {} ticks of this thread's CPU between {} sample calls: min {:?}, median {:?}, \
max {:?} (specified 25 ms); the tests' own reading of the thread's CPU clock over the whole \
probe: {own:?} in {took:?} of wall time",
ticks.len(),
"ioreport probe tick: {} ticks of this thread's CPU between {} sample calls: min {:?}, \
median {:?}, max {:?} (specified 25 ms of CPU, or a 500 ms wall cap); {capped} of them \
reached the cap instead, each reporting its own spin count; the tests' own reading of the \
thread's CPU clock over the whole probe: {own:?} in {took:?} of wall time",
gaps.len(),
run.calls.len(),
ticks.iter().min(),
(!ticks.is_empty()).then(|| median(&ticks)),
ticks.iter().max()
cpus.iter().min(),
(!cpus.is_empty()).then(|| median(&cpus)),
cpus.iter().max()
);
assert!(ticks.len() >= 2, "the probe made only {} sample calls", run.calls.len());
assert_eq!(run.ticks as usize, ticks.len(), "every tick runs between two sample calls");
for (i, t) in ticks.iter().enumerate() {
assert!(gaps.len() >= 2, "the probe made only {} sample calls", run.calls.len());
assert_eq!(run.ticks as usize, gaps.len(), "every tick runs between two sample calls");
assert_eq!(run.tick_outcomes.len(), gaps.len(), "every tick reported an outcome");
for (i, (&(cpu, wall), out)) in gaps.iter().zip(&run.tick_outcomes).enumerate() {
// The claim is that the probe BURNS CPU between samples rather
// than waiting or skipping, and that claim cannot be checked with
// a CPU threshold. A tick stops on the CPU target or on the wall
// cap; a host that gives this thread a sliver of a core caps it
// with little CPU to show, and a tick that merely *slept* looks
// the same in both clocks. A threshold between those two is a
// number the host can defeat in either direction — too low and a
// sleeping tick passes, too high and a starved one fails. So the
// tick reports its own spin count, and that is the separator: a
// tick that never span did not burn CPU, at any load.
assert!(
*t >= TICK / 2,
"tick {i} burned only {t:?} of this thread's CPU (every tick: {ticks:?}): the probe must burn \
CPU between samples, not wait or skip. A tick spins until the thread's CPU clock has \
advanced 25 ms, so host load cannot shorten it; only its 500 ms wall cap can, on a host \
that gives this thread under 5% of a core"
out.spins > 0,
"tick {i} reported {} turns of its spin loop: it did not burn CPU between samples, it \
waited or was skipped (outcome {out:?}, gap {cpu:?} of CPU in {wall:?} of wall time)",
out.spins
);
// And it stopped for one of the two stated reasons, not early.
assert!(
out.cpu >= crate::clocks::PROBE_TICK
|| wall + CLOCK_STEP >= crate::clocks::PROBE_TICK_WALL_CAP,
"tick {i} stopped after {:?} of CPU without reaching the 25 ms target, and only {wall:?} \
of wall time had passed — short of the 500 ms cap, so neither stopping condition had \
been met (outcome {out:?})",
out.cpu
);
assert!(
*t <= TICK * 2,
"tick {i} burned {t:?} of this thread's CPU (every tick: {ticks:?}): the tick is 25 ms of CPU"
cpu <= TICK * 2,
"tick {i} burned {cpu:?} of this thread's CPU (every gap: {gaps:?}): the tick is 25 ms of CPU"
);
assert!(
cpu <= wall + CLOCK_STEP,
"tick {i}: {cpu:?} of this thread's CPU in only {wall:?} of wall time"
);
// Deliberately NOT asserted: that each turn burned a minimum of
// thread CPU. The idea was that CPU per turn is fixed work, so
// starvation lowers turns-per-second and not the cost of a turn,
// which would separate a real spin from a loop that counts turns
// while sleeping through them. Measured, it does the opposite: a
// real turn costs 2.13-2.51 µs idle and 2.70-2.92 µs under
// eighteen competing busy loops, while a turn that sleeps 1 ms
// costs 13.3-15.8 µs — a blocking body's context switch is
// charged to this thread and costs it MORE CPU per turn than 256
// adds do. A floor would not discriminate, and a threshold that
// does not discriminate reads as a guarantee while being none.
//
// So the honest scope of this test: it establishes that every
// tick's spin loop ran, and that each tick stopped for one of its
// two stated reasons. It does not establish that the loop body is
// CPU-bound rather than blocking.
eprintln!(
" tick {i}: {:?} of CPU over {} spins = {:?}/spin, in {wall:?} of wall time",
out.cpu,
out.spins,
out.cpu.checked_div(u32::try_from(out.spins).unwrap_or(u32::MAX).max(1)).unwrap_or_default()
);
}
assert!(
own >= recorded,
"the probe recorded {recorded:?} of tick CPU, but this thread's CPU clock advanced only {own:?} \
over the whole probe"
"the probe recorded {recorded:?} of tick CPU, but this thread's CPU clock advanced only \
{own:?} over the whole probe"
);
}
@ -4004,10 +4130,10 @@ mod linux_rapl {
/// when every package counter reads, and is then sampled by
/// [`rail_liveness::probe_counter`], with `tick` between samples, by the
/// clock `now`: live only when every package counter keeps advancing.
pub(crate) fn status_with(
pub(crate) fn status_with<T>(
packages: &[Package],
read: impl Fn() -> Option<Vec<u64>>,
tick: impl FnMut(),
tick: impl FnMut() -> T,
now: impl Fn() -> Duration,
) -> CounterStatus {
if packages.is_empty() {
@ -4036,7 +4162,7 @@ mod linux_rapl {
/// One probe of the package zones under `root`: list them
/// ([`packages_under`]), then probe all of their counters together
/// ([`status_with`]).
pub(crate) fn probe_root(root: &Path, tick: impl FnMut(), now: impl Fn() -> Duration) -> Host {
pub(crate) fn probe_root<T>(root: &Path, tick: impl FnMut() -> T, now: impl Fn() -> Duration) -> Host {
let packages = packages_under(root);
let status = status_with(&packages, || read_packages(root, &packages), tick, now);
Host { packages, status }
@ -4609,9 +4735,9 @@ mod macos_process_energy {
/// counter reads at all, and is then sampled by
/// [`rail_liveness::probe_counter`], with `tick` between samples, by the
/// clock `now`.
pub(crate) fn status_with(
pub(crate) fn status_with<T>(
read: impl Fn() -> Option<u64>,
tick: impl FnMut(),
tick: impl FnMut() -> T,
now: impl Fn() -> std::time::Duration,
) -> CounterStatus {
rail_liveness::counter_status(

32
jouleclaw/jouleclaw-rs/crates/jouleclaw-energy/tests/process_cpu.rs
View file

@ -122,9 +122,37 @@ fn the_process_counter_meters_this_process_and_nothing_else() {
"process-cpu: child burned {:.3} J in 300 ms; this process's window = {parent:?} µJ",
child_burned_nj as f64 / 1e9
);
assert!(child_burned_nj >= 200_000_000, "the child did not burn: {child_burned_nj} nJ");
// The claim under test is *attribution*, so that is what is asserted: the
// child's burn against this process's window, not the child's burn against
// an absolute figure.
//
// The absolute floor was 0.2 J, and it made this test fail under host load —
// the child is an ordinary-priority shell loop competing for a core, so a
// busy host starves it below the line (seen on the dev Mac at load average
// 149: 0.147 J, and the test is also the macOS CI runner). How much work a
// competing process gets done in a 300 ms wall window is the host's
// scheduler talking, not this counter. The floor stays only to keep the
// check from being vacuous if the child never ran at all, an order of
// magnitude below anything a starved child has shown.
assert!(
child_burned_nj >= 20_000_000,
"the child did not burn at all: {child_burned_nj} nJ"
);
match parent {
Ok(uj) => assert!(uj < 100_000, "{uj} µJ in this process while only the child worked"),
Ok(uj) => {
// The real assertion, and a far wider margin than the old pair gave:
// 0.2 J against 0.1 J was a factor of two, while attribution either
// holds by orders of magnitude or does not hold. Observed in the
// starved run above: 147 032 342 nJ in the child against 137 000 nJ
// here — a factor of about 1 070.
let parent_nj = u128::from(uj) * 1_000;
assert!(
parent_nj * 10 < u128::from(child_burned_nj),
"this process's window is {uj} µJ ({parent_nj} nJ) against the child's \
{child_burned_nj} nJ: the child's work is being attributed here"
);
assert!(uj < 100_000, "{uj} µJ in this process while only the child worked");
}
Err(EnergyError::NotAdvanced) => {}
Err(e) => panic!("the parent window failed: {e}"),
}

182
proof/proof-rs/crates/proof-cascade/src/meter.rs
View file

@ -538,7 +538,7 @@ const RAPL_LIVENESS_BUDGET: std::time::Duration = std::time::Duration::from_mill
#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
fn rapl_probe_with(
zones: impl Fn() -> Vec<rapl::Zone>,
tick: impl FnMut(),
tick: impl FnMut() -> probe_clock::TickOutcome,
wall: impl Fn() -> std::time::Duration,
cpu: impl Fn() -> Option<std::time::Duration>,
budget: std::time::Duration,
@ -701,7 +701,7 @@ fn process_read(nj: u64) -> liveness::Read {
#[cfg_attr(not(target_os = "macos"), allow(dead_code))]
fn process_probe_with(
counter: impl Fn() -> Option<u64>,
tick: impl FnMut(),
tick: impl FnMut() -> probe_clock::TickOutcome,
wall: impl Fn() -> std::time::Duration,
cpu: impl Fn() -> Option<std::time::Duration>,
budget: std::time::Duration,
@ -1195,6 +1195,8 @@ mod liveness {
pub(super) opened: bool,
/// How many times the probe ticked (burned CPU before a re-read).
pub(super) ticks: u32,
/// What each of those ticks did, in order. `ticks` is its length.
pub(super) tick_outcomes: Vec<crate::meter::probe_clock::TickOutcome>,
/// Every read, in order, the baseline included.
pub(super) calls: Vec<SampleCall>,
/// What each successful read handed the rule, in order: one per
@ -1224,6 +1226,23 @@ mod liveness {
out
}
/// The wall time each interval between two consecutive successful reads
/// spanned, outside the reads themselves. The companion to
/// [`ProbeRun::interval_cpu`]: a tick stops on the CPU target OR the
/// wall cap, so the CPU figure alone cannot say whether a short tick was
/// starved into the cap or stopped early.
pub(super) fn interval_wall(&self) -> Vec<Duration> {
let mut out = Vec::new();
let mut prev_end: Option<Duration> = None;
for c in self.calls.iter().filter(|c| c.listed.is_some()) {
if let Some(end) = prev_end {
out.push(c.start.saturating_sub(end));
}
prev_end = Some(c.end);
}
out
}
/// The median thread CPU time one read took (the upper one of an even
/// count), over the reads whose CPU clock could be read; `None` if
/// there are none.
@ -1260,7 +1279,7 @@ mod liveness {
pub(super) fn probe_with<S>(
open: impl FnOnce() -> Option<S>,
read: impl FnMut(&S) -> Option<Read>,
tick: impl FnMut(),
tick: impl FnMut() -> crate::meter::probe_clock::TickOutcome,
wall: impl Fn() -> Duration,
cpu: impl Fn() -> Option<Duration>,
budget: Duration,
@ -1274,7 +1293,7 @@ mod liveness {
watched: Watched,
open: impl FnOnce() -> Option<S>,
mut read: impl FnMut(&S) -> Option<Read>,
mut tick: impl FnMut(),
mut tick: impl FnMut() -> crate::meter::probe_clock::TickOutcome,
wall: impl Fn() -> Duration,
cpu: impl Fn() -> Option<Duration>,
budget: Duration,
@ -1297,7 +1316,7 @@ mod liveness {
if !watch.wants_more(wall().saturating_sub(started), budget) {
break;
}
tick();
run.tick_outcomes.push(tick());
run.ticks += 1;
}
run.verdict = watch.verdict();
@ -1449,7 +1468,10 @@ mod liveness {
calls.set(n + 1);
script(n).map(|s| read_of(&s))
},
|| clock.set(clock.get() + tick),
|| {
clock.set(clock.get() + tick);
crate::meter::probe_clock::TickOutcome { cpu: None, spins: 1 }
},
|| clock.get(),
|| None,
BUDGET,
@ -2092,6 +2114,7 @@ mod liveness {
|| {
clock.set(clock.get() + TICK);
cpu.set(cpu.get() + TICK);
crate::meter::probe_clock::TickOutcome { cpu: Some(TICK), spins: 1 }
},
|| clock.get(),
|| Some(cpu.get()),
@ -2343,28 +2366,59 @@ mod probe_clock {
/// spins [`PROBE_TICK`] of wall time. The burn cannot manufacture `Live`
/// — only a counter's own raw integer that keeps advancing can — so a
/// short burn errs only toward declining, the safe side.
pub(super) fn spin_tick() {
burn_thread_cpu(PROBE_TICK, TICK_WALL_CAP);
pub(super) fn spin_tick() -> TickOutcome {
burn_thread_cpu(PROBE_TICK, TICK_WALL_CAP)
}
fn burn_thread_cpu(cpu: Duration, wall_cap: Duration) {
/// What one tick did.
///
/// `spins` is why this type exists. A tick stops on either of two
/// conditions — the CPU target or the wall cap — and from the outside the
/// two outcomes that matter are not separable by time: a spin the host
/// starved into the cap and a tick that simply *slept* both show a long wall
/// span against little CPU. Nor does CPU-per-turn separate them, measured:
/// a turn that blocks costs the thread MORE CPU than a turn of arithmetic,
/// because its context switch is charged to the thread. The only honest
/// separator is whether the loop ran at all, and only the loop can report
/// that.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub(super) struct TickOutcome {
/// The thread CPU the tick saw itself burn, where the clock is readable.
pub(super) cpu: Option<Duration>,
/// Turns of the spin loop. Zero means the tick never span.
pub(super) spins: u64,
}
fn burn_thread_cpu(cpu: Duration, wall_cap: Duration) -> TickOutcome {
let wall = Instant::now();
let mut acc: u64 = 0;
let mut spins: u64 = 0;
let Some(start) = thread_cpu_time() else {
while wall.elapsed() < cpu {
spins += 1;
acc = std::hint::black_box(acc.wrapping_add(1));
}
return;
std::hint::black_box(acc);
return TickOutcome { cpu: None, spins };
};
let mut used = Duration::ZERO;
while wall.elapsed() < wall_cap {
spins += 1;
for _ in 0..4096 {
acc = std::hint::black_box(acc.wrapping_add(1));
}
match thread_cpu_time() {
Some(now) if now.saturating_sub(start) < cpu => {}
_ => break,
Some(now) => {
used = now.saturating_sub(start);
if used >= cpu {
break;
}
}
None => break,
}
}
std::hint::black_box(acc);
TickOutcome { cpu: Some(used), spins }
}
}
@ -3682,10 +3736,13 @@ mod macos_ioreport {
/// read listed the Energy Model group alone — every channel in that
/// group, as many as the group has, far fewer than every channel — and
/// the median thread CPU of its reads stays under 50 ms. R2: every
/// interval burned at least `PROBE_TICK / 2` of the probing thread's
/// CPU between reads. No wall-clock bound or ratio: another process
/// sampling IOReport makes this probe wait, never changes what it
/// listed or what it burned. Returns the structural line to log.
/// tick's spin loop ran, and every interval either reached the tick of
/// CPU or spent the wall cap. It is not a CPU floor: a tick stops on
/// either condition, so a floor bounds the host's scheduler rather than
/// the probe. The reads themselves carry no wall-clock bound either —
/// another process sampling IOReport makes this probe wait, never
/// changes what it listed or what it burned. Returns the structural
/// line to log.
fn assert_sampling(run: &ProbeRun, who: &str, group: &Group) -> String {
if !run.opened {
assert_eq!(run.verdict, None, "{who}: no Energy Model subscription, yet a verdict");
@ -3721,17 +3778,41 @@ mod macos_ioreport {
run.calls.len()
);
let cpu = run.interval_cpu();
let wall = run.interval_wall();
assert_eq!(cpu.len(), run.intervals as usize, "{who}: one CPU figure per interval");
for (i, c) in cpu.iter().enumerate() {
assert_eq!(wall.len(), cpu.len(), "{who}: one wall figure per interval");
assert_eq!(
run.tick_outcomes.len(),
run.ticks as usize,
"{who}: every tick reported an outcome"
);
// The claim is that the probe burns CPU before each re-read, and a
// CPU floor cannot check it. A tick stops on the CPU target OR the
// {TICK_WALL:?} wall cap, so a host that gives this thread a sliver
// of a core caps the tick with little CPU to show — this assertion
// used to require half of {TICK_CPU:?} and failed on the macOS
// runner that way, under other work on the same machine. Nor does
// CPU-per-turn separate a starved spin from a tick that slept:
// measured, a blocking turn costs the thread MORE CPU than an
// arithmetic one, because its context switch is charged here. So the
// tick reports whether its loop ran at all, which no load can forge.
for (i, out) in run.tick_outcomes.iter().enumerate() {
assert!(
out.spins > 0,
"{who}: tick {i} of {} reported {} turns of its spin loop: the probe is not burning CPU \
before each re-read, it waited or skipped (outcome {out:?})",
run.ticks,
out.spins
);
}
for (i, (c, w)) in cpu.iter().zip(&wall).enumerate() {
let c = c.unwrap_or_else(|| panic!("{who}: interval {i}: this thread's CPU clock could not be read"));
assert!(
c >= TICK_CPU / 2,
"{who}: interval {i} of {} consumed {c:?} of the probing thread's CPU time between reads, under \
{:?}: the probe is not burning CPU before each re-read. The tick burns thread CPU time, so host \
load does not shorten it; only its {TICK_WALL:?} wall-clock cap can, which takes this thread \
being starved of the CPU for that long",
run.intervals,
TICK_CPU / 2
c >= TICK_CPU || *w + Duration::from_millis(1) >= TICK_WALL,
"{who}: interval {i} of {} consumed {c:?} of the probing thread's CPU time between reads in \
{w:?} of wall time: short of the {TICK_CPU:?} tick, and short of the {TICK_WALL:?} wall cap, \
so neither stopping condition had been met",
run.intervals
);
}
format!(
@ -4285,11 +4366,11 @@ mod macos_ioreport {
/// The REAL production composition, `host_status()`, run on this thread
/// with every channel read scripted — read `n` lists `script(n)` — and
/// the real tick and clocks. Anything between the raw channel read and
/// the rule runs as in production. Checks, on the tests' own thread CPU
/// clock, that the run's real ticks burned this thread's CPU: at least
/// `TICK_CPU / 2` per tick over the whole call, the bound
/// [`assert_sampling`] puts on each interval through the production
/// clock.
/// the rule runs as in production. Checks that every one of the run's
/// real ticks actually span, which is what "burned CPU" means here and
/// the only form of it a loaded host cannot forge — see
/// [`assert_sampling`] for why a CPU floor, aggregate or per interval,
/// bounds the scheduler rather than the probe.
fn host_status_scripted(script: fn(u32) -> Vec<(&'static str, i64)>) -> HostStatus {
let mut n = 0u32;
let next = move || {
@ -4301,13 +4382,20 @@ mod macos_ioreport {
let hs = seam::with(seam::Mode::Script(Box::new(next)), host_status);
let burned = test_thread_cpu() - c0;
assert!(hs.run.ticks > 0, "a scripted run that never ticked: {:?}", hs.run);
assert!(
burned >= TICK_CPU / 2 * hs.run.ticks,
"host_status() ticked {} times, yet this thread burned only {burned:?} of CPU (tests' clock) in the \
whole call: under {:?} a tick",
hs.run.ticks,
TICK_CPU / 2
);
// Per tick, that its spin loop ran — not an aggregate CPU floor.
// A floor of half a tick per tick is a bound on what the host's
// scheduler allowed, not on what the probe did: every tick can hit
// its wall cap on a loaded box and the total falls under the line
// while the probe behaved correctly.
for (i, out) in hs.run.tick_outcomes.iter().enumerate() {
assert!(
out.spins > 0,
"host_status() tick {i} of {} reported {} turns of its spin loop: it did not burn CPU \
(outcome {out:?}, this thread burned {burned:?} over the whole call)",
hs.run.ticks,
out.spins
);
}
hs
}
@ -4468,8 +4556,16 @@ mod macos_ioreport {
assert_eq!((run.calls.len(), run.ticks as usize), (run.intervals as usize + 1, run.intervals as usize));
assert_verdict_matches_record(run, "scripted sustained advance");
assert_handed_the_script(run, advancing);
// Covered per tick by `assert_sampling` above; here only that every
// interval's CPU was readable at all. The old `>= TICK_CPU / 2` was
// a bound on the host's scheduler, not on the probe.
let cpu = run.interval_cpu();
assert!(cpu.iter().all(|c| c.is_some_and(|c| c >= TICK_CPU / 2)), "the real tick did not burn: {cpu:?}");
assert!(cpu.iter().all(Option::is_some), "an interval's thread CPU clock could not be read: {cpu:?}");
assert!(
run.tick_outcomes.iter().all(|t| t.spins > 0),
"a real tick did not spin: {:?}",
run.tick_outcomes
);
}
/// `host_status()` on the two-step refresh observed on an M5 Max: the
@ -4855,6 +4951,10 @@ mod tests {
ticks.set(ticks.get() + 1);
clock.set(clock.get() + Duration::from_millis(25));
cpu.set(cpu.get() + Duration::from_millis(25));
crate::meter::probe_clock::TickOutcome {
cpu: Some(Duration::from_millis(25)),
spins: 1,
}
},
|| clock.get(),
|| Some(cpu.get()),
@ -4953,6 +5053,10 @@ mod tests {
ticks.set(ticks.get() + 1);
clock.set(clock.get() + Duration::from_millis(25));
cpu.set(cpu.get() + Duration::from_millis(25));
crate::meter::probe_clock::TickOutcome {
cpu: Some(Duration::from_millis(25)),
spins: 1,
}
},
|| clock.get(),
|| Some(cpu.get()),
@ -5141,6 +5245,10 @@ mod tests {
ticks.set(ticks.get() + 1);
clock.set(clock.get() + Duration::from_millis(25));
cpu.set(cpu.get() + Duration::from_millis(25));
crate::meter::probe_clock::TickOutcome {
cpu: Some(Duration::from_millis(25)),
spins: 1,
}
},
|| clock.get(),
|| Some(cpu.get()),

19
sandbox/sandbox-rs/crates/sandbox-exec-microvm/src/power.rs
View file

@ -22,7 +22,7 @@
//! run. A meter that did not open, or whose count broke, samples `None`, and
//! the executor estimates.
use sandbox_meter::probe::{ProbeError, RaplPackages};
use sandbox_meter::probe::{ProbeError, RaplPackages, TickOutcome};
use std::path::Path;
use std::sync::Mutex;
@ -66,7 +66,7 @@ impl RaplMeter {
/// one proves live under the same rule, with `tick` driving the load
/// between liveness samples. For a tree other than the host's sysfs: a
/// test's fake tree.
pub fn live_in(root: &Path, tick: impl FnMut()) -> RaplMeter {
pub fn live_in(root: &Path, tick: impl FnMut() -> TickOutcome) -> RaplMeter {
Self::opened(RaplPackages::live_in(root, tick))
}
@ -100,7 +100,7 @@ pub use msr::MsrRaplMeter;
#[cfg(any(target_os = "linux", all(test, unix)))]
mod msr {
use super::PowerMeter;
use sandbox_meter::probe::{counter_liveness, CounterStatus};
use sandbox_meter::probe::{counter_liveness, CounterStatus, TickOutcome};
use std::collections::BTreeMap;
use std::os::unix::fs::FileExt;
use std::path::{Path, PathBuf};
@ -165,7 +165,7 @@ mod msr {
/// and `dev/cpu`), only when every one proves live, with `tick`
/// driving the load between liveness samples. For a tree other than
/// the host's: a test's fake tree. Not cached.
pub fn live_in(root: &Path, tick: impl FnMut()) -> Result<MsrRaplMeter, String> {
pub fn live_in(root: &Path, tick: impl FnMut() -> TickOutcome) -> Result<MsrRaplMeter, String> {
Self::given(root, status_over(root, tick))
}
@ -203,7 +203,7 @@ mod msr {
/// The liveness run over the domains of the tree at `root`: never ticked
/// if they do not open.
fn status_over(root: &Path, tick: impl FnMut()) -> CounterStatus {
fn status_over(root: &Path, tick: impl FnMut() -> TickOutcome) -> CounterStatus {
counter_liveness(|| MsrDomains::open_in(root).ok().map(|d| move || d.raw_sample()), tick)
}
@ -464,8 +464,13 @@ mod tests {
/// The liveness tick the tests drive: a sleep, while a writer thread
/// advances the counters.
fn sleep_tick() {
/// A scripted stand-in for the production burn: these trees are fakes and
/// the load that matters is the script's writes. It reports a turn, so the
/// probe's "did the tick run" rule is satisfied honestly rather than by a
/// figure that happens to clear a threshold.
fn sleep_tick() -> TickOutcome {
std::thread::sleep(Duration::from_millis(25));
TickOutcome { cpu: Duration::from_millis(25), spins: 1 }
}
/// A VMM whose "run" is a script over the fake tree.
@ -619,6 +624,7 @@ mod tests {
let ticks = AtomicUsize::new(0);
let meter = RaplMeter::live_in(&tree.root, || {
ticks.fetch_add(1, SeqCst);
TickOutcome { cpu: Duration::ZERO, spins: 1 }
});
let why = meter.unavailable().expect("opened").to_string();
assert!(why.contains("RAPL"), "{why}");
@ -780,6 +786,7 @@ mod tests {
let ticks = AtomicUsize::new(0);
match msr::MsrRaplMeter::live_in(&tree.root, || {
ticks.fetch_add(1, SeqCst);
TickOutcome { cpu: Duration::ZERO, spins: 1 }
}) {
Err(why) => assert!(why.contains(expect), "{expect}: {why}"),
Ok(m) => panic!("{expect}: opened {:?}", m.domains()),

52
sandbox/sandbox-rs/crates/sandbox-meter/src/probe/ioreport.rs
View file

@ -183,9 +183,9 @@ fn thread_cpu() -> Duration {
/// The real probe's tick: [`spin`] on this thread's CPU clock, capped on a
/// monotonic one.
fn probe_tick() {
fn probe_tick() -> super::liveness::TickOutcome {
let t = Instant::now();
spin(thread_cpu, || t.elapsed());
spin(thread_cpu, || t.elapsed())
}
/// Convert a channel reading to microjoules by its unit label.
@ -585,9 +585,11 @@ mod tests {
assert!(cpu <= wall + ms(1), "{which}: {cpu:?} of one thread's CPU in {wall:?} of wall time");
}
/// The probe's tick burns CPU on the calling thread; it does not sleep,
/// and it burns a full tick of this thread's CPU however loaded the
/// machine is. Five ticks, each measured on the tests' own clock.
/// The probe's tick burns CPU on the calling thread; it does not sleep.
/// Each tick reaches a full tick of this thread's CPU, or stops at its wall
/// cap — the second is what a host that starves this thread produces, and
/// claiming otherwise is what made the interval assertion below fail in CI.
/// Five ticks, each measured on the tests' own clock.
#[test]
fn the_probe_tick_burns_cpu_on_the_calling_thread() {
for i in 0..5 {
@ -1415,16 +1417,44 @@ mod tests {
run.interval_burn
);
let least = run.interval_burn.iter().min().copied().unwrap_or_default();
assert_eq!(
run.interval_wall.len(),
run.interval_burn.len(),
"one wall figure per interval: {:?}",
run.interval_wall
);
assert_eq!(run.tick_outcomes.len(), run.ticks as usize, "every tick reported an outcome");
eprintln!(
"ioreport probe burn: {intervals} intervals, the least thread CPU burned in one {least:?} (tick \
{PROBE_TICK:?})"
{PROBE_TICK:?}, or a {TICK_WALL_CAP:?} wall cap); {} of {} ticks stopped under the tick",
run.tick_outcomes.iter().filter(|t| t.cpu < PROBE_TICK).count(),
run.ticks
);
for (i, burned) in run.interval_burn.iter().enumerate() {
// The claim is that the probe burns CPU between its samples, and a CPU
// floor cannot check it. A tick stops on the CPU target OR the
// {TICK_WALL_CAP:?} cap, so a host that gives this thread a sliver of a
// core caps the tick with little CPU to show — this assertion used to
// require half a tick and the comment beside it claimed load could not
// shorten a tick, which is what the wall cap does. Nor does
// CPU-per-turn separate a starved spin from a tick that slept:
// measured, a blocking turn costs the thread MORE CPU than an
// arithmetic one, its context switch being charged here. So the tick
// reports whether its loop ran, which no load can forge.
for (i, out) in run.tick_outcomes.iter().enumerate() {
assert!(
*burned >= PROBE_TICK / 2,
"interval {i} of {intervals}: the probe burned {burned:?} of this thread's CPU between its samples, \
under half its {PROBE_TICK:?} tick. A tick burns until this thread's CPU clock has advanced a full \
tick, however loaded the machine is; only its {TICK_WALL_CAP:?} wall cap can cut it short"
out.spins > 0,
"tick {i} of {} reported {} turns of its spin loop: the probe is not burning CPU between its \
samples, it waited or skipped (outcome {out:?})",
run.ticks,
out.spins
);
}
for (i, (burned, wall)) in run.interval_burn.iter().zip(&run.interval_wall).enumerate() {
assert!(
*burned >= PROBE_TICK || *wall + ms(1) >= TICK_WALL_CAP,
"interval {i} of {intervals}: the probe burned {burned:?} of this thread's CPU between its samples \
in {wall:?} of wall time: short of its {PROBE_TICK:?} tick, and short of the {TICK_WALL_CAP:?} \
wall cap, so neither stopping condition had been met"
);
}
}

80
sandbox/sandbox-rs/crates/sandbox-meter/src/probe/liveness.rs
View file

@ -345,9 +345,9 @@ pub(super) fn rail_advances<'a>(before: &[(String, i64)], after: &'a [(String, i
/// A sample that could not be read is skipped, not fatal: the next one that
/// can be read closes the interval, and a host whose samples never read runs
/// to the cap and gets no verdict.
pub(super) fn watch(
pub(super) fn watch<T>(
mut sample: impl FnMut() -> Option<Sample>,
mut tick: impl FnMut(),
mut tick: impl FnMut() -> T,
now: impl Fn() -> Duration,
budget: Duration,
) -> RailWatch {
@ -367,31 +367,54 @@ pub(super) fn watch(
/// The probe's tick: burn CPU on the calling thread until its CPU clock `cpu`
/// has advanced [`PROBE_TICK`], or [`TICK_WALL_CAP`] has passed on the wall
/// clock `wall`. Returns the CPU time `cpu` saw burned.
/// clock `wall`. Returns a [`TickOutcome`].
///
/// The probe spins rather than sleeps, because a rail that advances only
/// under load must see load between the samples. It counts THIS thread's CPU
/// time, not wall time, so a loaded machine that takes CPU from the thread
/// makes the tick longer, never lighter: every interval carries a full tick
/// of burn. The clocks are passed in so the rule is tested with scripted
/// ones; the real probe passes this thread's CPU clock and a monotonic one.
pub(super) fn spin(cpu: impl Fn() -> Duration, wall: impl Fn() -> Duration) -> Duration {
/// The probe spins rather than sleeps, because a rail that advances only under
/// load must see load between the samples. It counts THIS thread's CPU time,
/// not wall time, so a loaded machine that takes CPU from the thread makes the
/// tick longer rather than lighter — **up to the wall cap**, which is where that
/// stops being true: a thread given a sliver of a core hits the cap with little
/// CPU burned, and the interval then carries less than a full tick. That is why
/// the outcome reports its spin count and not only its CPU. The clocks are
/// passed in so the rule is tested with scripted ones; the real probe passes
/// this thread's CPU clock and a monotonic one.
pub(super) fn spin(cpu: impl Fn() -> Duration, wall: impl Fn() -> Duration) -> TickOutcome {
spin_for(PROBE_TICK, cpu, wall)
}
/// What one tick did.
///
/// `spins` is why this is a struct and not a `Duration`. A tick stops on
/// either of two conditions — the CPU target or [`TICK_WALL_CAP`] — and the two
/// outcomes that matter are not separable by time: a spin the host starved into
/// the cap and a tick that simply *slept* both show a long wall span against
/// little CPU. Nor does CPU-per-turn separate them, measured: a turn that
/// blocks costs the thread MORE CPU than a turn of arithmetic, because its
/// context switch is charged to the thread. The only honest separator is
/// whether the loop ran at all, and only the loop can report that.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub struct TickOutcome {
/// The thread CPU the tick saw itself burn.
pub cpu: Duration,
/// Turns of the spin loop. Zero means the tick never span.
pub spins: u64,
}
/// [`spin`] for a tick of `tick` of this thread's CPU time, still capped at
/// [`TICK_WALL_CAP`] of wall time.
pub(super) fn spin_for(tick: Duration, cpu: impl Fn() -> Duration, wall: impl Fn() -> Duration) -> Duration {
pub(super) fn spin_for(tick: Duration, cpu: impl Fn() -> Duration, wall: impl Fn() -> Duration) -> TickOutcome {
let (cpu0, wall0) = (cpu(), wall());
let mut acc: u64 = 0;
let mut spins: u64 = 0;
loop {
spins += 1;
for _ in 0..1_000 {
acc = acc.wrapping_mul(6364136223846793005).wrapping_add(1442695040888963407);
}
std::hint::black_box(acc);
let burned = cpu().saturating_sub(cpu0);
if burned >= tick || wall().saturating_sub(wall0) >= TICK_WALL_CAP {
return burned;
return TickOutcome { cpu: burned, spins };
}
}
}
@ -435,7 +458,7 @@ pub(super) fn admits(status: IoReportStatus) -> bool {
/// gives no verdict.
pub(super) fn counter_run<R>(
open: impl FnOnce() -> Option<R>,
tick: impl FnMut(),
tick: impl FnMut() -> TickOutcome,
now: impl Fn() -> Duration,
budget: Duration,
) -> RailWatch
@ -575,9 +598,9 @@ pub(super) fn thread_cpu() -> Duration {
/// A counter probe's real tick: [`spin_for`] `tick` of this thread's CPU
/// time, capped on a monotonic clock.
#[cfg(any(target_os = "macos", target_os = "linux"))]
pub(super) fn counter_tick(tick: Duration) {
pub(super) fn counter_tick(tick: Duration) -> TickOutcome {
let t = std::time::Instant::now();
spin_for(tick, thread_cpu, || t.elapsed());
spin_for(tick, thread_cpu, || t.elapsed())
}
/// What one sample call of a probe run cost, and what the sample held.
@ -611,6 +634,12 @@ pub(super) struct ProbeRun {
/// that were read), the CPU time the ticks burned in it, measured around
/// the ticks, apart from the samples' own cost.
pub(super) interval_burn: Vec<Duration>,
/// The same intervals in wall time. A tick stops on the CPU target OR the
/// wall cap, so `interval_burn` alone cannot say whether a light interval
/// was starved into the cap or stopped early.
pub(super) interval_wall: Vec<Duration>,
/// What each tick did, in order. `ticks` is its length.
pub(super) tick_outcomes: Vec<TickOutcome>,
}
impl ProbeRun {
@ -637,7 +666,7 @@ impl ProbeRun {
/// apart from the samples.
pub(super) fn probe_with<R>(
open: impl FnOnce() -> Option<R>,
mut tick: impl FnMut(),
mut tick: impl FnMut() -> TickOutcome,
cpu: impl Fn() -> Duration,
wall: impl Fn() -> Duration,
budget: Duration,
@ -649,9 +678,11 @@ where
return ProbeRun::default();
};
let (calls, interval_burn) = (RefCell::new(Vec::new()), RefCell::new(Vec::new()));
let (interval_wall, tick_outcomes) = (RefCell::new(Vec::new()), RefCell::new(Vec::new()));
// Tick CPU since the last sample that was read, how many samples were
// read, and how many ticks ran.
let (burn, reads, ticks) = (Cell::new(Duration::ZERO), Cell::new(0u32), Cell::new(0u32));
let span = Cell::new(Duration::ZERO);
let watch = watch(
|| {
let (cpu0, started) = (cpu(), wall());
@ -668,17 +699,20 @@ where
if rails.is_some() {
if reads.get() > 0 {
interval_burn.borrow_mut().push(burn.get());
interval_wall.borrow_mut().push(span.get());
}
reads.set(reads.get() + 1);
burn.set(Duration::ZERO);
span.set(Duration::ZERO);
}
rails
},
|| {
let before = cpu();
tick();
let (before, wall_before) = (cpu(), wall());
tick_outcomes.borrow_mut().push(tick());
ticks.set(ticks.get() + 1);
burn.set(burn.get() + cpu().saturating_sub(before));
span.set(span.get() + wall().saturating_sub(wall_before));
},
&wall,
budget,
@ -689,6 +723,8 @@ where
calls: calls.into_inner(),
ticks: ticks.get(),
interval_burn: interval_burn.into_inner(),
interval_wall: interval_wall.into_inner(),
tick_outcomes: tick_outcomes.into_inner(),
}
}
@ -1262,6 +1298,7 @@ mod tests {
wall.get()
},
);
let burned = burned.cpu;
assert!(burned >= PROBE_TICK, "the tick stopped after {burned:?} of this thread's CPU");
assert!(burned < PROBE_TICK + ms(2), "the tick burned past {PROBE_TICK:?}: {burned:?}");
assert!(wall.get() >= ms(70) && wall.get() < TICK_WALL_CAP, "wall {:?}", wall.get());
@ -1279,7 +1316,8 @@ mod tests {
wall.get()
},
);
assert_eq!(burned, Duration::ZERO);
assert_eq!(burned.cpu, Duration::ZERO);
assert!(burned.spins > 0, "a tick that burned nothing still span: {burned:?}");
assert!(wall.get() >= TICK_WALL_CAP && wall.get() < TICK_WALL_CAP + ms(30), "wall {:?}", wall.get());
}
@ -1519,6 +1557,7 @@ mod tests {
ticks.set(ticks.get() + 1);
cpu.set(cpu.get() + tick);
wall.set(wall.get() + tick);
TickOutcome { cpu: tick, spins: 1 }
},
|| cpu.get(),
|| wall.get(),
@ -1739,6 +1778,7 @@ mod tests {
|| {
ticks.set(ticks.get() + 1);
clock.set(clock.get() + tick);
TickOutcome { cpu: tick, spins: 1 }
},
|| clock.get(),
BUDGET,
@ -1968,7 +2008,7 @@ mod tests {
wall.get()
},
);
assert!(burned >= NVML_PROBE_TICK && burned < NVML_PROBE_TICK + ms(2), "{burned:?}");
assert!(burned.cpu >= NVML_PROBE_TICK && burned.cpu < NVML_PROBE_TICK + ms(2), "{burned:?}");
}
/// The gate as a constructor: a counter that is not live is never

25
sandbox/sandbox-rs/crates/sandbox-meter/src/probe/mod.rs
View file

@ -60,6 +60,10 @@ mod process;
// sysfs tree.
mod rapl;
pub use rapl::RaplPackages;
// Part of the public surface because it appears in one: `RaplPackages::live_in`
// and `counter_liveness` take a tick that returns it, so a caller outside this
// crate has to be able to name it and build one.
pub use liveness::TickOutcome;
pub mod attribute;
pub use attribute::{run_attributed, Attribution};
@ -254,7 +258,10 @@ pub fn rapl_status() -> CounterStatus {
/// held or stepped only in a burst; `Unavailable` if the counter did not open
/// (never sampled or ticked), could not be read twice, or has no rail. The
/// caller caches the status as it sees fit; nothing here is cached.
pub fn counter_liveness<R>(open: impl FnOnce() -> Option<R>, tick: impl FnMut()) -> CounterStatus
pub fn counter_liveness<R>(
open: impl FnOnce() -> Option<R>,
tick: impl FnMut() -> liveness::TickOutcome,
) -> CounterStatus
where
R: FnMut() -> Option<Vec<(String, i64)>>,
{
@ -268,8 +275,8 @@ where
/// 25 ms of the calling thread's CPU time, capped at 500 ms of wall time —
/// the `tick` to hand [`counter_liveness`] for a real counter.
#[cfg(any(target_os = "macos", target_os = "linux"))]
pub fn counter_liveness_tick() {
liveness::counter_tick(liveness::PROBE_TICK);
pub fn counter_liveness_tick() -> TickOutcome {
liveness::counter_tick(liveness::PROBE_TICK)
}
/// This host's NVML status, probed once per process and cached.
@ -1060,7 +1067,12 @@ mod tests {
/// open is `Unavailable` and never ticked.
#[test]
fn counter_liveness_holds_a_callers_counter_to_the_every_rail_rule() {
let tick = || std::thread::sleep(Duration::from_millis(25));
// A scripted stand-in for the burn; it reports a turn so the rule that
// separates a spin from a wait is satisfied honestly.
let tick = || {
std::thread::sleep(Duration::from_millis(25));
liveness::TickOutcome { cpu: Duration::from_millis(25), spins: 1 }
};
let n = std::cell::Cell::new(0i64);
let both = || {
n.set(n.get() + 1);
@ -1075,7 +1087,10 @@ mod tests {
assert_eq!(counter_liveness(|| Some(one_held), tick), CounterStatus::Frozen);
let ticks = std::cell::Cell::new(0);
type Sampler = fn() -> Option<Vec<(String, i64)>>;
let none = counter_liveness(|| None::<Sampler>, || ticks.set(ticks.get() + 1));
let none = counter_liveness(|| None::<Sampler>, || {
ticks.set(ticks.get() + 1);
liveness::TickOutcome { cpu: Duration::ZERO, spins: 1 }
});
assert_eq!((none, ticks.get()), (CounterStatus::Unavailable, 0));
}
}

16
sandbox/sandbox-rs/crates/sandbox-meter/src/probe/rapl.rs
View file

@ -102,7 +102,7 @@ fn real_run() -> RailWatch {
/// given `tick` and a monotonic clock, for [`CPU_RAIL_LIVENESS_BUDGET`]. A
/// tree that does not open (absent, unreadable, no package zone) is never
/// ticked.
fn run_over(root: &Path, tick: impl FnMut()) -> RailWatch {
fn run_over(root: &Path, tick: impl FnMut() -> crate::probe::liveness::TickOutcome) -> RailWatch {
let epoch = Instant::now();
counter_run(
|| RaplProbe::open_in(root).ok().map(|p| move || p.raw_sample()),
@ -243,7 +243,10 @@ impl RaplPackages {
/// other than the host's sysfs: a test's fake tree. Not cached; the run
/// takes about 300 ms over live counters and the whole
/// [`CPU_RAIL_LIVENESS_BUDGET`] over a held one.
pub fn live_in(root: &Path, tick: impl FnMut()) -> Result<RaplPackages, ProbeError> {
pub fn live_in(
root: &Path,
tick: impl FnMut() -> crate::probe::liveness::TickOutcome,
) -> Result<RaplPackages, ProbeError> {
let status = counter_status_of(run_over(root, tick).verdict());
gated("RAPL", status, || RaplProbe::open_in(root)).map(|probe| RaplPackages { probe })
}
@ -561,6 +564,9 @@ mod tests {
tree.write(dir, &uj.to_string());
}
std::thread::sleep(Duration::from_millis(25));
// A scripted tick: it stands in for the burn, and says so by
// reporting a turn.
crate::probe::liveness::TickOutcome { cpu: Duration::from_millis(25), spins: 1 }
});
let status = counter_status_of(watch.verdict());
eprintln!("rapl run: zones {advancing:?} advancing, the rest holding -> {status:?}");
@ -580,7 +586,10 @@ mod tests {
);
let psys_only = FakePowercap::with_zones(&[("intel-rapl:0", Some("psys"), "90000", Some("262143328850"))]);
let ticks = std::cell::Cell::new(0);
let watch = run_over(&psys_only.root, || ticks.set(ticks.get() + 1));
let watch = run_over(&psys_only.root, || {
ticks.set(ticks.get() + 1);
crate::probe::liveness::TickOutcome { cpu: Duration::ZERO, spins: 1 }
});
assert_eq!((counter_status_of(watch.verdict()), ticks.get()), (CounterStatus::Unavailable, 0));
}
@ -686,6 +695,7 @@ mod tests {
tree.write(dir, &uj.to_string());
}
std::thread::sleep(Duration::from_millis(25));
crate::probe::liveness::TickOutcome { cpu: Duration::from_millis(25), spins: 1 }
})
}
let tree = two_sockets_with_psys_and_dram();

8
sandbox/sandbox-rs/crates/sandbox-meter/tests/rapl_hardware.rs
View file

@ -20,7 +20,7 @@ use std::path::Path;
use std::sync::{Mutex, MutexGuard};
use std::time::{Duration, Instant};
use sandbox_meter::probe::{rapl_status, CounterStatus, PowerMeter, RaplPackages};
use sandbox_meter::probe::{rapl_status, CounterStatus, PowerMeter, RaplPackages, TickOutcome};
use sandbox_meter::Provenance;
use sandbox_schema::DeviceClass;
@ -484,7 +484,11 @@ fn the_ci_containers_masked_view_is_unavailable() {
let view = oracle::MaskedView::of_host("sandbox-meter");
let watch = oracle::watch(&view.0);
let opened = RaplPackages::live_in(&view.0, || {
oracle::burn(Duration::from_millis(25), Duration::from_millis(500));
// The oracle's own burn, independent of the probe's. The spin count is
// this test's declaration that a real spin ran, not a reading taken
// from the probe — the oracle stays independent of what it checks.
let cpu = oracle::burn(Duration::from_millis(25), Duration::from_millis(500));
TickOutcome { cpu, spins: 1 }
});
eprintln!("rapl masked view: oracle {}; probe {:?}", watch.summary(), opened.as_ref().map(|p| p.zones().len()).map_err(|e| e.to_string()));
assert!(matches!(watch.verdict, Verdict::Unreadable | Verdict::NoPackage), "{watch:?}");