Merge pull request #126 from moka-rs/quanta-v0.10

Upgrade quanta to v0.10.0

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 ## Version 0.8.4
 
+### Fixed
+
+- Fix the issue [#119][gh-issue-0119] by upgrading Quanta crate to v0.10.0.
+  ([#126][gh-pull-0126])
+    - Quanta v0.9.3 or older may not work correctly on some x86_64 machines where
+      the Time Stamp Counter (TSC) is not synched across the processor cores.
+    - For more details about the issue, see [the relevant section][panic_in_quanta]
+      of the README.
+
+
 ### Added
 
 - Add `get_with_if` method to the following caches: ([#123][gh-issue-0123])
@@ -19,8 +29,10 @@
     - Quanta v0.9.3 or older may not work correctly on some x86_64 machines where
       the Time Stamp Counter (TSC) is not synched across the processor cores.
       ([#119][gh-issue-0119])
-    - You can avoid the issue by disabling the default features of Moka.
-      See [the relevant section][panic_in_quanta] of the README.
+    - This issue was fixed by Quanta v0.10.0. You can upgrade Moka to v0.8.4 or newer
+      to prevent the issue.
+    - For more details about the issue, see [the relevant section][panic_in_quanta]
+      of the README.
 
 
 ## Version 0.8.2
@@ -334,6 +346,7 @@ The minimum supported Rust version (MSRV) is now 1.51.0 (2021-03-25).
 [gh-issue-0038]: https://github.com/moka-rs/moka/issues/38/
 [gh-issue-0031]: https://github.com/moka-rs/moka/issues/31/
 
+[gh-pull-0126]: https://github.com/moka-rs/moka/pull/126/
 [gh-pull-0121]: https://github.com/moka-rs/moka/pull/121/
 [gh-pull-0117]: https://github.com/moka-rs/moka/pull/117/
 [gh-pull-0116]: https://github.com/moka-rs/moka/pull/116/

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moka"
-version = "0.8.3"
+version = "0.8.4"
 edition = "2018"
 rust-version = "1.51"
 
@@ -55,7 +55,7 @@ uuid = { version = "0.8", features = ["v4"] }
 triomphe = { version = "0.1", default-features = false }
 
 # Optional dependencies (quanta, enabled by default)
-quanta = { version = "0.9.3", optional = true }
+quanta = { version = "0.10.0", optional = true }
 
 # Optional dependencies (dashmap)
 dashmap = { version = "5.2", optional = true }

README.md

@@ -437,13 +437,14 @@ change.
 
 ### Integer Overflow in Quanta Crate on Some x86_64 Machines
 
-Quanta crate has a known issue on some specific x86_64-based machines. It will cause
-intermittent panic due to integer overflow:
+Quanta crate up to v0.9.3 has an issue on some specific x86_64-based machines. It
+will cause intermittent panic due to integer overflow:
 
--  metrics-rs/quanta — [Intermittent panic due to overflowing our source calibration denominator. #61](https://github.com/metrics-rs/quanta/issues/61)
+- metrics-rs/quanta — [Intermittent panic due to overflowing our source calibration denominator. #61](https://github.com/metrics-rs/quanta/issues/61)
+  (Fixed by Quanta v0.10.0)
 
 The overflows have been reported by a couple of users who use AMD-based Lenovo
-laptops or Circle CI. There is no fix available yet as of Quanta v0.9.3.
+laptops or Circle CI.
 
 When this issue occurs, you will get a stacktrace containing the following lines:
 
@@ -457,18 +458,10 @@ quanta::Clock::new::{{closure}}
 ...
 ```
 
-You can avoid the issue by disabling `qanta` feature, which is one of the default
-features of Moka. Edit your Cargo.toml to add `default-features = false` to the
-dependency declaration.
+This issue was fixed by Quanta v0.10.0.
 
-```toml:Cargo.toml
-[dependencies]
-moka = { version = "0.8", default-feautures = false }
-# Or
-moka = { version = "0.8", default-feautures = false, features = ["future"] }
-```
-
-This will make Moka to opt out Quanta and switch to a fall-back implementation.
+You can prevent the issue by upgrading Moka to v0.8.4 or newer, which depends on
+Quanta v0.10.0 or newer.
 
 
 ### Compile Errors on Some 32-bit Platforms

src/common/time.rs

@@ -26,7 +26,7 @@ pub(crate) use clock::Mock;
 /// a wrapper type over Instant to force checked additions and prevent
 /// unintentional overflow. The type preserve the Copy semantics for the wrapped
 #[derive(PartialEq, PartialOrd, Clone, Copy)]
-pub(crate) struct Instant(pub clock::Instant);
+pub(crate) struct Instant(clock::Instant);
 
 pub(crate) trait CheckedTimeOps {
     fn checked_add(&self, duration: Duration) -> Option<Self>

src/common/time/atomic_time.rs

@@ -1,6 +1,9 @@
 use super::Instant;
 
-use std::sync::atomic::{AtomicU64, Ordering};
+use std::{
+    any::TypeId,
+    sync::atomic::{AtomicU64, Ordering},
+};
 
 pub(crate) struct AtomicInstant {
     instant: AtomicU64,
@@ -14,6 +17,9 @@ impl Default for AtomicInstant {
     }
 }
 
+// TODO: Need a safe way to convert between `quanta::Instant` and `u64`.
+// quanta v0.10.0 no longer provides `quanta::Instant::as_u64` method.
+
 impl AtomicInstant {
     pub(crate) fn reset(&self) {
         self.instant.store(std::u64::MAX, Ordering::Release);
@@ -28,11 +34,20 @@ impl AtomicInstant {
         if ts == u64::MAX {
             None
         } else {
-            Some(unsafe { std::mem::transmute(ts) })
+            debug_assert_eq!(
+                TypeId::of::<super::clock::Instant>(),
+                TypeId::of::<quanta::Instant>()
+            );
+            Some(Instant(unsafe { std::mem::transmute(ts) }))
         }
     }
 
     pub(crate) fn set_instant(&self, instant: Instant) {
-        self.instant.store(instant.0.as_u64(), Ordering::Release);
+        debug_assert_eq!(
+            TypeId::of::<super::clock::Instant>(),
+            TypeId::of::<quanta::Instant>()
+        );
+        let ts = unsafe { std::mem::transmute(instant.0) };
+        self.instant.store(ts, Ordering::Release);
     }
 }