quanta 0.12.3

high-speed timing library
Documentation 
# Changelog
All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project
adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

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## [Unreleased] - ReleaseDate

## [0.12.3] - 2024-03-31

### Changed

- Disabled counter support on iOS targets even if AArch64 is present. This is due to an issue where
  the necessary CPU instruction for reading the counter is not available on iOS.

## [0.12.2] - 2023-12-31

### Fixed

- Fixed an issue with the monotonic clock for macOS/iOS where it would undermeasure time compared to
  what would be measured by `std::time::Instant` due to using a clock source that did not account
  for device sleep. ([#97](https://github.com/metrics-rs/quanta/pull/97))

## [0.12.1] - 2023-10-31

### Fixed

- Populate global recent time before `Upkeep` starts. ([#95])

[#95]: https://github.com/metrics-rs/quanta/pull/95

## [0.12.0] - 2023-10-04

### Added

- Experimental support for ARM. ([#91])

[#91]: https://github.com/metrics-rs/quanta/pull/91 

### Changed

- Update `raw-cpuid` to 11.0.

## [0.11.1] - 2023-05-28

### Added

- Added a new method, `Clock::delta_as_nanos`, for getting the delta between two raw measurements as
  the whole number of nanoseconds instead of the initial conversion to `Duration`. ([#86])

[#86]: https://github.com/metrics-rs/quanta/pull/86

## [0.11.0] - 2023-03-24

### Added

- `Instant::elapsed()` has been added. ([#82])

### Changed

- `Instant::duration_since` and `Instant::sub` now saturates to zero. ([#82])
- Performance of `Instant::now` under high contention has been improved. ([#82])

[#82]: https://github.com/metrics-rs/quanta/pull/82

## [0.10.1] - 2022-07-20

### Added

- Implement `std::error::Error` for `quanta::Error`. ([#68])

### Changed

- Fixed build issue on x86/x86_64 platforms that did not have SSE.
- Fix scaling factor for `window.performance.now()` in WASM. ([#72])

[#72]: https://github.com/metrics-rs/quanta/pull/72
[#68]: https://github.com/metrics-rs/quanta/pull/68

## [0.10.0] - 2022-05-18

### Changed

- Documentation has been updated to reflect that `quanta` does not track time across system
  suspends.
- Fixed a panic in the calibration loop if a certain edge case with TSC measurements is encountered.
- Updated a unit test that was frequently flaky to be more precise.

### Removed

- `Instant::as_u64` has been removed.  As it provided direct access to an value that could
  fundamentally change from version-to-version, it felt like time to remove that footgun and push
  users more towards the API that mimics `std::time`.
- `Clock::upkeep` has been removed.  It doesn't need to exist on `Clock` directly, as we have had
  the `quanta::set_recent` free function for a while now, and was just duplicating that.
- `Clock::start` and `Clock::end` have been removed. They saw limited usage and overall just added somewhat needless API
  clutter given that users who are looking to do ultra-precise timing will either want more control or use another
  technique such as instruction counting.

## 0.9.3 - 2021-09-16

### Added

- CI tests for MIPS/ARM. ([#55](https://github.com/metrics-rs/quanta/pull/55))

### Changed

- Fixed compilation issue with `Mock` on MIPS/ARM. ([#55](https://github.com/metrics-rs/quanta/pull/55))
- Simplified how TSC/RDTSC suppoort is detected, which should avoid some situations where it was
  assumed to be present, but actually was not. ([#57](https://github.com/metrics-rs/quanta/pull/57))

## 0.9.2 - 2021-08-25

### Changed

- Pinned `crossbeam-utils` to `v0.8.5` where `AtomicCell::fetch_update` was introduced to fix, which
  fixes broken builds where Cargo chooses a version between `0.8.0` and `0.8.5`.
- Update `raw-cpuid` to `10.2` and `average` to `0.13`.

## 0.9.1 - 2021-08-12

### Changed

- Switched from `atomic-shim` to `crossbeam-utils` for better cross-platform atomic support. ([#52](https://github.com/metrics-rs/quanta/pull/52))

## 0.9.0 - 2021-06-17

### Added

- Support for WASM/WASI targets. ([#45](https://github.com/metrics-rs/quanta/pull/45))

## 0.8.0 - 2021-06-07

### Removed

- `Instant::as_unix_duration` as it was added in error.
- `metrics` feature flag as `metrics-core` is no longer a relevant crate.

## 0.7.2 - 2021-01-25
### Changed

- Bumped dependency on `raw-cpuid` to `9.0` in order to deal with a [RustSec
  advisory](https://rustsec.org/advisories/RUSTSEC-2021-0013).

## 0.7.1 - 2021-01-24
### Fixed

- Incorrect method visibility for non-SSE2 implementation of `Counter`.
  ([#38](https://github.com/metrics-rs/quanta/issues/38))

## 0.7.0 - 2021-01-03
### Changed

- MSRV bumped to 1.45.0.
- `Clock::now` takes `&self` instead of `&mut self`.
- Fixed a bug where a failure to spawn the upkeep thread would not allow subsequent attempts to
  spawn the upkeep thread to proceed.

### Added

- New methods --`Instant::now` and `Instant::recent` for getting the current and recent time,
  respectively.
- New free function `quanta::with_clock` for setting an override on the current thread that affects
  calls made to `Instant::now` and `Instant::recent`.
- New free function `quanta::set_recent` to allow customization of how global recent time is
  updated.

## 0.6.5 - 2020-09-16
### Changed

- Fixed a bug with not being able to start the upkeep thread at all.
  ([#29](https://github.com/metrics-rs/quanta/issues/29))

## 0.6.4 - 2020-08-27
### Added

- Add `Instant::as_unix_duration` to get the duration of time since the Unix epoch from an
  `Instant`.
  ### Changed
- Remove `clocksource` from dependencies and tests as it no longer compiles on stable or nightly.

## 0.6.3 - 2020-08-03
### Changed

- Publicly expose `Clock::upkeep` for advanced use cases.
- Relax constraints around checking for multiple sockets.
  ([#25](https://github.com/metrics-rs/quanta/issues/25))

## 0.6.2 - 2020-07-20
### Added

- Add support for MIPS/PowerPC. ([#23](https://github.com/metrics-rs/quanta/pull/23))

## 0.6.1 - 2020-07-13
### Added

- Publicly expose the `Error` type returned by `Upkeep::start`.

## 0.6.0 - 2020-07-06

This version of `quanta` was a massive overhaul of man areas of the API and internals, which was
done in a single PR: ([#19](https://github.com/metrics-rs/quanta/pull/19)).  You can read the PR
description for the finer details.  All changes below are part of the aforementioned PR.

### Changed

- `Clock::now` now returns a monotonic value in all cases.
- No longer possible to get a negative value from `Clock::delta`.
- Calibration is no longer a fixed one second loop, and will complete when it detects it has a
  statistically viable calibration ratio, or when it exceeds 200ms of wall-clock time.  In most
  cases, it should complete in under 10ms.
- Calibration is now shared amongst all `Clock` instances, running only once when the first `Clock`
  is created.

## 0.5.2 - 2020-05-01
### Changed

- Fix the logic to figure out when calibration is required.
  ([#14](https://github.com/metrics-rs/quanta/pull/14))

## 0.5.1 - 2020-04-11
### Changed

- Small tweak to the docs.

## 0.5.0 - 2020-04-11
### Changed

- Switch to `mach` for macOS/iOS as it was deprecated in `libc`.
  ([#12](https://github.com/metrics-rs/quanta/pull/12))
- Switch to `core::arch` for instrinics, and drop the feature flagged configuration to use it.
  ([#12](https://github.com/metrics-rs/quanta/pull/12))
- Switch to `criterion` for benchmarking. ([#12](https://github.com/metrics-rs/quanta/pull/12))

## 0.4.0 - 2020-02-20
### Changed

- Differentiate between raw and scaled time by adding a new `Instant` type.
  ([#10](https://github.com/metrics-rs/quanta/pull/10))

## 0.2.0 - 2019-03-10
### Changed

- Fixed support for Windows.  It was in a bad way, but actually works correctly now!
- Switched to Azure Pipelines CI + Cirrus CI, including formatting, tests, and benchmarks, for
  Linux, macOS, Windows, and FreeBSD.

## 0.1.0 - 2019-01-14
### Added

- Initial commit.

<!-- next-url -->
[Unreleased]: https://github.com/metrics-rs/quanta/compare/v0.12.3...HEAD
[0.12.3]: https://github.com/metrics-rs/quanta/compare/v0.12.2...v0.12.3
[0.12.2]: https://github.com/metrics-rs/quanta/compare/v0.12.1...v0.12.2
[0.12.1]: https://github.com/metrics-rs/quanta/compare/v0.12.0...v0.12.1
[0.12.0]: https://github.com/metrics-rs/quanta/compare/v0.11.1...v0.12.0
[0.11.1]: https://github.com/metrics-rs/quanta/compare/v0.11.0...v0.11.1
[0.11.0]: https://github.com/metrics-rs/quanta/compare/v0.10.1...v0.11.0
[0.10.1]: https://github.com/metrics-rs/quanta/compare/v0.10.0...v0.10.1
[0.10.0]: https://github.com/metrics-rs/quanta/releases/tag/v0.10.0