runtime: update the alignment of CachePadded (#5106)

tokio/src/runtime/time/entry.rs

@@ -642,7 +642,73 @@ impl Drop for TimerEntry {
     }
 }
 
-#[cfg_attr(target_arch = "x86_64", repr(align(128)))]
-#[cfg_attr(not(target_arch = "x86_64"), repr(align(64)))]
+// Copied from [crossbeam/cache_padded](https://github.com/crossbeam-rs/crossbeam/blob/fa35346b7c789bba045ad789e894c68c466d1779/crossbeam-utils/src/cache_padded.rs#L62-L127)
+//
+// Starting from Intel's Sandy Bridge, spatial prefetcher is now pulling pairs of 64-byte cache
+// lines at a time, so we have to align to 128 bytes rather than 64.
+//
+// Sources:
+// - https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf
+// - https://github.com/facebook/folly/blob/1b5288e6eea6df074758f877c849b6e73bbb9fbb/folly/lang/Align.h#L107
+//
+// ARM's big.LITTLE architecture has asymmetric cores and "big" cores have 128-byte cache line size.
+//
+// Sources:
+// - https://www.mono-project.com/news/2016/09/12/arm64-icache/
+//
+// powerpc64 has 128-byte cache line size.
+//
+// Sources:
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_ppc64x.go#L9
+#[cfg_attr(
+    any(
+        target_arch = "x86_64",
+        target_arch = "aarch64",
+        target_arch = "powerpc64",
+    ),
+    repr(align(128))
+)]
+// arm, mips, mips64, and riscv64 have 32-byte cache line size.
+//
+// Sources:
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_arm.go#L7
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips.go#L7
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mipsle.go#L7
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips64x.go#L9
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_riscv64.go#L7
+#[cfg_attr(
+    any(
+        target_arch = "arm",
+        target_arch = "mips",
+        target_arch = "mips64",
+        target_arch = "riscv64",
+    ),
+    repr(align(32))
+)]
+// s390x has 256-byte cache line size.
+//
+// Sources:
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_s390x.go#L7
+#[cfg_attr(target_arch = "s390x", repr(align(256)))]
+// x86 and wasm have 64-byte cache line size.
+//
+// Sources:
+// - https://github.com/golang/go/blob/dda2991c2ea0c5914714469c4defc2562a907230/src/internal/cpu/cpu_x86.go#L9
+// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_wasm.go#L7
+//
+// All others are assumed to have 64-byte cache line size.
+#[cfg_attr(
+    not(any(
+        target_arch = "x86_64",
+        target_arch = "aarch64",
+        target_arch = "powerpc64",
+        target_arch = "arm",
+        target_arch = "mips",
+        target_arch = "mips64",
+        target_arch = "riscv64",
+        target_arch = "s390x",
+    )),
+    repr(align(64))
+)]
 #[derive(Debug, Default)]
 struct CachePadded<T>(T);