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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
use std::collections::HashMap;
use std::mem;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::{Arc, Mutex};
use std::time::Duration;
use crate::common_metric_data::CommonMetricDataInternal;
use crate::error_recording::{record_error, test_get_num_recorded_errors, ErrorType};
use crate::histogram::{Functional, Histogram};
use crate::metrics::time_unit::TimeUnit;
use crate::metrics::{DistributionData, Metric, MetricType};
use crate::storage::StorageManager;
use crate::CommonMetricData;
use crate::Glean;
// The base of the logarithm used to determine bucketing
const LOG_BASE: f64 = 2.0;
// The buckets per each order of magnitude of the logarithm.
const BUCKETS_PER_MAGNITUDE: f64 = 8.0;
// Maximum time, which means we retain a maximum of 316 buckets.
// It is automatically adjusted based on the `time_unit` parameter
// so that:
//
// - `nanosecond` - 10 minutes
// - `microsecond` - ~6.94 days
// - `millisecond` - ~19 years
const MAX_SAMPLE_TIME: u64 = 1000 * 1000 * 1000 * 60 * 10;
/// Identifier for a running timer.
///
/// Its internals are considered private,
/// but due to UniFFI's behavior we expose its field for now.
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub struct TimerId {
/// This timer's id.
pub id: u64,
}
impl From<u64> for TimerId {
fn from(val: u64) -> TimerId {
TimerId { id: val }
}
}
impl From<usize> for TimerId {
fn from(val: usize) -> TimerId {
TimerId { id: val as u64 }
}
}
/// A timing distribution metric.
///
/// Timing distributions are used to accumulate and store time measurement, for analyzing distributions of the timing data.
#[derive(Clone, Debug)]
pub struct TimingDistributionMetric {
meta: Arc<CommonMetricDataInternal>,
time_unit: TimeUnit,
next_id: Arc<AtomicUsize>,
start_times: Arc<Mutex<HashMap<TimerId, u64>>>,
}
/// Create a snapshot of the histogram with a time unit.
///
/// The snapshot can be serialized into the payload format.
pub(crate) fn snapshot(hist: &Histogram<Functional>) -> DistributionData {
DistributionData {
// **Caution**: This cannot use `Histogram::snapshot_values` and needs to use the more
// specialized snapshot function.
values: hist
.snapshot()
.into_iter()
.map(|(k, v)| (k as i64, v as i64))
.collect(),
sum: hist.sum() as i64,
count: hist.count() as i64,
}
}
impl MetricType for TimingDistributionMetric {
fn meta(&self) -> &CommonMetricDataInternal {
&self.meta
}
fn with_name(&self, name: String) -> Self {
let mut meta = (*self.meta).clone();
meta.inner.name = name;
Self {
meta: Arc::new(meta),
time_unit: self.time_unit,
next_id: Arc::new(AtomicUsize::new(1)),
start_times: Arc::new(Mutex::new(Default::default())),
}
}
fn with_dynamic_label(&self, label: String) -> Self {
let mut meta = (*self.meta).clone();
meta.inner.dynamic_label = Some(label);
Self {
meta: Arc::new(meta),
time_unit: self.time_unit,
next_id: Arc::new(AtomicUsize::new(1)),
start_times: Arc::new(Mutex::new(Default::default())),
}
}
}
// IMPORTANT:
//
// When changing this implementation, make sure all the operations are
// also declared in the related trait in `../traits/`.
impl TimingDistributionMetric {
/// Creates a new timing distribution metric.
pub fn new(meta: CommonMetricData, time_unit: TimeUnit) -> Self {
Self {
meta: Arc::new(meta.into()),
time_unit,
next_id: Arc::new(AtomicUsize::new(1)),
start_times: Arc::new(Mutex::new(Default::default())),
}
}
/// Starts tracking time for the provided metric.
///
/// This records an error if it’s already tracking time (i.e.
/// [`set_start`](TimingDistributionMetric::set_start) was already called with no
/// corresponding [`set_stop_and_accumulate`](TimingDistributionMetric::set_stop_and_accumulate)): in
/// that case the original start time will be preserved.
///
/// # Arguments
///
/// * `start_time` - Timestamp in nanoseconds.
///
/// # Returns
///
/// A unique [`TimerId`] for the new timer.
pub fn start(&self) -> TimerId {
let start_time = time::precise_time_ns();
let id = self.next_id.fetch_add(1, Ordering::SeqCst).into();
let metric = self.clone();
crate::launch_with_glean(move |_glean| metric.set_start(id, start_time));
id
}
pub(crate) fn start_sync(&self) -> TimerId {
let start_time = time::precise_time_ns();
let id = self.next_id.fetch_add(1, Ordering::SeqCst).into();
let metric = self.clone();
metric.set_start(id, start_time);
id
}
/// **Test-only API (exported for testing purposes).**
///
/// Set start time for this metric synchronously.
///
/// Use [`start`](Self::start) instead.
#[doc(hidden)]
pub fn set_start(&self, id: TimerId, start_time: u64) {
let mut map = self.start_times.lock().expect("can't lock timings map");
map.insert(id, start_time);
}
/// Stops tracking time for the provided metric and associated timer id.
///
/// Adds a count to the corresponding bucket in the timing distribution.
/// This will record an error if no
/// [`set_start`](TimingDistributionMetric::set_start) was called.
///
/// # Arguments
///
/// * `id` - The [`TimerId`] to associate with this timing. This allows
/// for concurrent timing of events associated with different ids to the
/// same timespan metric.
/// * `stop_time` - Timestamp in nanoseconds.
pub fn stop_and_accumulate(&self, id: TimerId) {
let stop_time = time::precise_time_ns();
let metric = self.clone();
crate::launch_with_glean(move |glean| metric.set_stop_and_accumulate(glean, id, stop_time));
}
fn set_stop(&self, id: TimerId, stop_time: u64) -> Result<u64, (ErrorType, &str)> {
let mut start_times = self.start_times.lock().expect("can't lock timings map");
let start_time = match start_times.remove(&id) {
Some(start_time) => start_time,
None => return Err((ErrorType::InvalidState, "Timing not running")),
};
let duration = match stop_time.checked_sub(start_time) {
Some(duration) => duration,
None => {
return Err((
ErrorType::InvalidValue,
"Timer stopped with negative duration",
))
}
};
Ok(duration)
}
/// **Test-only API (exported for testing purposes).**
///
/// Set stop time for this metric synchronously.
///
/// Use [`stop_and_accumulate`](Self::stop_and_accumulate) instead.
#[doc(hidden)]
pub fn set_stop_and_accumulate(&self, glean: &Glean, id: TimerId, stop_time: u64) {
if !self.should_record(glean) {
let mut start_times = self.start_times.lock().expect("can't lock timings map");
start_times.remove(&id);
return;
}
// Duration is in nanoseconds.
let mut duration = match self.set_stop(id, stop_time) {
Err((err_type, err_msg)) => {
record_error(glean, &self.meta, err_type, err_msg, None);
return;
}
Ok(duration) => duration,
};
let min_sample_time = self.time_unit.as_nanos(1);
let max_sample_time = self.time_unit.as_nanos(MAX_SAMPLE_TIME);
duration = if duration < min_sample_time {
// If measurement is less than the minimum, just truncate. This is
// not recorded as an error.
min_sample_time
} else if duration > max_sample_time {
let msg = format!(
"Sample is longer than the max for a time_unit of {:?} ({} ns)",
self.time_unit, max_sample_time
);
record_error(glean, &self.meta, ErrorType::InvalidOverflow, msg, None);
max_sample_time
} else {
duration
};
if !self.should_record(glean) {
return;
}
// Let's be defensive here:
// The uploader tries to store some timing distribution metrics,
// but in tests that storage might be gone already.
// Let's just ignore those.
// We do the same for counters.
// This should never happen in real app usage.
if let Some(storage) = glean.storage_opt() {
storage.record_with(glean, &self.meta, |old_value| match old_value {
Some(Metric::TimingDistribution(mut hist)) => {
hist.accumulate(duration);
Metric::TimingDistribution(hist)
}
_ => {
let mut hist = Histogram::functional(LOG_BASE, BUCKETS_PER_MAGNITUDE);
hist.accumulate(duration);
Metric::TimingDistribution(hist)
}
});
} else {
log::warn!(
"Couldn't get storage. Can't record timing distribution '{}'.",
self.meta.base_identifier()
);
}
}
/// Aborts a previous [`start`](Self::start) call.
///
/// No error is recorded if no [`start`](Self::start) was called.
///
/// # Arguments
///
/// * `id` - The [`TimerId`] to associate with this timing. This allows
/// for concurrent timing of events associated with different ids to the
/// same timing distribution metric.
pub fn cancel(&self, id: TimerId) {
let metric = self.clone();
crate::launch_with_glean(move |_glean| metric.cancel_sync(id));
}
/// Aborts a previous [`start`](Self::start) call synchronously.
pub(crate) fn cancel_sync(&self, id: TimerId) {
let mut map = self.start_times.lock().expect("can't lock timings map");
map.remove(&id);
}
/// Accumulates the provided signed samples in the metric.
///
/// This is required so that the platform-specific code can provide us with
/// 64 bit signed integers if no `u64` comparable type is available. This
/// will take care of filtering and reporting errors for any provided negative
/// sample.
///
/// Please note that this assumes that the provided samples are already in
/// the "unit" declared by the instance of the metric type (e.g. if the
/// instance this method was called on is using [`TimeUnit::Second`], then
/// `samples` are assumed to be in that unit).
///
/// # Arguments
///
/// * `samples` - The vector holding the samples to be recorded by the metric.
///
/// ## Notes
///
/// Discards any negative value in `samples` and report an [`ErrorType::InvalidValue`]
/// for each of them. Reports an [`ErrorType::InvalidOverflow`] error for samples that
/// are longer than `MAX_SAMPLE_TIME`.
pub fn accumulate_samples(&self, samples: Vec<i64>) {
let metric = self.clone();
crate::launch_with_glean(move |glean| metric.accumulate_samples_sync(glean, &samples))
}
/// Accumulates precisely one signed sample and appends it to the metric.
///
/// Precludes the need for a collection in the most common use case.
///
/// Sign is required so that the platform-specific code can provide us with
/// a 64 bit signed integer if no `u64` comparable type is available. This
/// will take care of filtering and reporting errors for any provided negative
/// sample.
///
/// Please note that this assumes that the provided sample is already in
/// the "unit" declared by the instance of the metric type (e.g. if the
/// instance this method was called on is using [`crate::TimeUnit::Second`], then
/// `sample` is assumed to be in that unit).
///
/// # Arguments
///
/// * `sample` - The singular sample to be recorded by the metric.
///
/// ## Notes
///
/// Discards any negative value and reports an [`ErrorType::InvalidValue`].
/// Reports an [`ErrorType::InvalidOverflow`] error if the sample is longer than
/// `MAX_SAMPLE_TIME`.
pub fn accumulate_single_sample(&self, sample: i64) {
let metric = self.clone();
crate::launch_with_glean(move |glean| metric.accumulate_samples_sync(glean, &[sample]))
}
/// **Test-only API (exported for testing purposes).**
/// Accumulates the provided signed samples in the metric.
///
/// Use [`accumulate_samples`](Self::accumulate_samples)
#[doc(hidden)]
pub fn accumulate_samples_sync(&self, glean: &Glean, samples: &[i64]) {
if !self.should_record(glean) {
return;
}
let mut num_negative_samples = 0;
let mut num_too_long_samples = 0;
let max_sample_time = self.time_unit.as_nanos(MAX_SAMPLE_TIME);
glean.storage().record_with(glean, &self.meta, |old_value| {
let mut hist = match old_value {
Some(Metric::TimingDistribution(hist)) => hist,
_ => Histogram::functional(LOG_BASE, BUCKETS_PER_MAGNITUDE),
};
for &sample in samples.iter() {
if sample < 0 {
num_negative_samples += 1;
} else {
let mut sample = sample as u64;
// Check the range prior to converting the incoming unit to
// nanoseconds, so we can compare against the constant
// MAX_SAMPLE_TIME.
if sample == 0 {
sample = 1;
} else if sample > MAX_SAMPLE_TIME {
num_too_long_samples += 1;
sample = MAX_SAMPLE_TIME;
}
sample = self.time_unit.as_nanos(sample);
hist.accumulate(sample);
}
}
Metric::TimingDistribution(hist)
});
if num_negative_samples > 0 {
let msg = format!("Accumulated {} negative samples", num_negative_samples);
record_error(
glean,
&self.meta,
ErrorType::InvalidValue,
msg,
num_negative_samples,
);
}
if num_too_long_samples > 0 {
let msg = format!(
"{} samples are longer than the maximum of {}",
num_too_long_samples, max_sample_time
);
record_error(
glean,
&self.meta,
ErrorType::InvalidOverflow,
msg,
num_too_long_samples,
);
}
}
/// Accumulates the provided samples in the metric.
///
/// # Arguments
///
/// * `samples` - A list of samples recorded by the metric.
/// Samples must be in nanoseconds.
/// ## Notes
///
/// Reports an [`ErrorType::InvalidOverflow`] error for samples that
/// are longer than `MAX_SAMPLE_TIME`.
pub fn accumulate_raw_samples_nanos(&self, samples: Vec<u64>) {
let metric = self.clone();
crate::launch_with_glean(move |glean| {
metric.accumulate_raw_samples_nanos_sync(glean, &samples)
})
}
/// Accumulates precisely one duration to the metric.
///
/// Like `TimingDistribution::accumulate_single_sample`, but for use when the
/// duration is:
///
/// * measured externally, or
/// * is in a unit different from the timing_distribution's internal TimeUnit.
///
/// # Arguments
///
/// * `duration` - The single duration to be recorded in the metric.
///
/// ## Notes
///
/// Reports an [`ErrorType::InvalidOverflow`] error if `duration` is longer than
/// `MAX_SAMPLE_TIME`.
///
/// The API client is responsible for ensuring that `duration` is derived from a
/// monotonic clock source that behaves consistently over computer sleep across
/// the application's platforms. Otherwise the resulting data may not share the same
/// guarantees that other `timing_distribution` metrics' data do.
pub fn accumulate_raw_duration(&self, duration: Duration) {
let duration_ns = duration.as_nanos().try_into().unwrap_or(u64::MAX);
let metric = self.clone();
crate::launch_with_glean(move |glean| {
metric.accumulate_raw_samples_nanos_sync(glean, &[duration_ns])
})
}
/// **Test-only API (exported for testing purposes).**
///
/// Accumulates the provided samples in the metric.
///
/// Use [`accumulate_raw_samples_nanos`](Self::accumulate_raw_samples_nanos) instead.
#[doc(hidden)]
pub fn accumulate_raw_samples_nanos_sync(&self, glean: &Glean, samples: &[u64]) {
if !self.should_record(glean) {
return;
}
let mut num_too_long_samples = 0;
let min_sample_time = self.time_unit.as_nanos(1);
let max_sample_time = self.time_unit.as_nanos(MAX_SAMPLE_TIME);
glean.storage().record_with(glean, &self.meta, |old_value| {
let mut hist = match old_value {
Some(Metric::TimingDistribution(hist)) => hist,
_ => Histogram::functional(LOG_BASE, BUCKETS_PER_MAGNITUDE),
};
for &sample in samples.iter() {
let mut sample = sample;
if sample < min_sample_time {
sample = min_sample_time;
} else if sample > max_sample_time {
num_too_long_samples += 1;
sample = max_sample_time;
}
// `sample` is in nanoseconds.
hist.accumulate(sample);
}
Metric::TimingDistribution(hist)
});
if num_too_long_samples > 0 {
let msg = format!(
"{} samples are longer than the maximum of {}",
num_too_long_samples, max_sample_time
);
record_error(
glean,
&self.meta,
ErrorType::InvalidOverflow,
msg,
num_too_long_samples,
);
}
}
/// Gets the currently stored value as an integer.
#[doc(hidden)]
pub fn get_value<'a, S: Into<Option<&'a str>>>(
&self,
glean: &Glean,
ping_name: S,
) -> Option<DistributionData> {
let queried_ping_name = ping_name
.into()
.unwrap_or_else(|| &self.meta().inner.send_in_pings[0]);
match StorageManager.snapshot_metric_for_test(
glean.storage(),
queried_ping_name,
&self.meta.identifier(glean),
self.meta.inner.lifetime,
) {
Some(Metric::TimingDistribution(hist)) => Some(snapshot(&hist)),
_ => None,
}
}
/// **Test-only API (exported for FFI purposes).**
///
/// Gets the currently stored value as an integer.
///
/// This doesn't clear the stored value.
///
/// # Arguments
///
/// * `ping_name` - the optional name of the ping to retrieve the metric
/// for. Defaults to the first value in `send_in_pings`.
///
/// # Returns
///
/// The stored value or `None` if nothing stored.
pub fn test_get_value(&self, ping_name: Option<String>) -> Option<DistributionData> {
crate::block_on_dispatcher();
crate::core::with_glean(|glean| self.get_value(glean, ping_name.as_deref()))
}
/// **Exported for test purposes.**
///
/// Gets the number of recorded errors for the given metric and error type.
///
/// # Arguments
///
/// * `error` - The type of error
///
/// # Returns
///
/// The number of errors reported.
pub fn test_get_num_recorded_errors(&self, error: ErrorType) -> i32 {
crate::block_on_dispatcher();
crate::core::with_glean(|glean| {
test_get_num_recorded_errors(glean, self.meta(), error).unwrap_or(0)
})
}
/// **Experimental:** Start a new histogram buffer associated with this timing distribution metric.
///
/// A histogram buffer accumulates in-memory.
/// Data is recorded into the metric on drop.
pub fn start_buffer(&self) -> LocalTimingDistribution<'_> {
LocalTimingDistribution::new(self)
}
fn commit_histogram(&self, histogram: Histogram<Functional>, errors: usize) {
let metric = self.clone();
crate::launch_with_glean(move |glean| {
if errors > 0 {
let max_sample_time = metric.time_unit.as_nanos(MAX_SAMPLE_TIME);
let msg = format!(
"{} samples are longer than the maximum of {}",
errors, max_sample_time
);
record_error(
glean,
&metric.meta,
ErrorType::InvalidValue,
msg,
Some(errors as i32),
);
}
glean
.storage()
.record_with(glean, &metric.meta, move |old_value| {
let mut hist = match old_value {
Some(Metric::TimingDistribution(hist)) => hist,
_ => Histogram::functional(LOG_BASE, BUCKETS_PER_MAGNITUDE),
};
hist.merge(&histogram);
Metric::TimingDistribution(hist)
});
});
}
}
/// **Experimental:** A histogram buffer associated with a specific instance of a [`TimingDistributionMetric`].
///
/// Accumulation happens in-memory.
/// Data is merged into the metric on [`Drop::drop`].
#[derive(Debug)]
pub struct LocalTimingDistribution<'a> {
histogram: Histogram<Functional>,
metric: &'a TimingDistributionMetric,
errors: usize,
}
impl<'a> LocalTimingDistribution<'a> {
/// Create a new histogram buffer referencing the timing distribution it will record into.
fn new(metric: &'a TimingDistributionMetric) -> Self {
let histogram = Histogram::functional(LOG_BASE, BUCKETS_PER_MAGNITUDE);
Self {
histogram,
metric,
errors: 0,
}
}
/// Accumulates one sample into the histogram.
///
/// The provided sample must be in the "unit" declared by the instance of the metric type
/// (e.g. if the instance this method was called on is using [`crate::TimeUnit::Second`], then
/// `sample` is assumed to be in seconds).
///
/// Accumulation happens in-memory only.
pub fn accumulate(&mut self, sample: u64) {
// Check the range prior to converting the incoming unit to
// nanoseconds, so we can compare against the constant
// MAX_SAMPLE_TIME.
let sample = if sample == 0 {
1
} else if sample > MAX_SAMPLE_TIME {
self.errors += 1;
MAX_SAMPLE_TIME
} else {
sample
};
let sample = self.metric.time_unit.as_nanos(sample);
self.histogram.accumulate(sample)
}
/// Abandon this histogram buffer and don't commit accumulated data.
pub fn abandon(mut self) {
self.histogram.clear();
}
}
impl Drop for LocalTimingDistribution<'_> {
fn drop(&mut self) {
if self.histogram.is_empty() {
return;
}
// We want to move that value.
// A `0/0` histogram doesn't allocate.
let buffer = mem::replace(&mut self.histogram, Histogram::functional(0.0, 0.0));
self.metric.commit_histogram(buffer, self.errors);
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn can_snapshot() {
use serde_json::json;
let mut hist = Histogram::functional(2.0, 8.0);
for i in 1..=10 {
hist.accumulate(i);
}
let snap = snapshot(&hist);
let expected_json = json!({
"sum": 55,
"values": {
"1": 1,
"2": 1,
"3": 1,
"4": 1,
"5": 1,
"6": 1,
"7": 1,
"8": 1,
"9": 1,
"10": 1,
"11": 0,
},
});
assert_eq!(expected_json, json!(snap));
}
#[test]
fn can_snapshot_sparse() {
use serde_json::json;
let mut hist = Histogram::functional(2.0, 8.0);
hist.accumulate(1024);
hist.accumulate(1024);
hist.accumulate(1116);
hist.accumulate(1448);
let snap = snapshot(&hist);
let expected_json = json!({
"sum": 4612,
"values": {
"1024": 2,
"1116": 1,
"1217": 0,
"1327": 0,
"1448": 1,
"1579": 0,
},
});
assert_eq!(expected_json, json!(snap));
}
}