CachePadded: update alignment based on golang's CacheLinePadSize

Refs: crossbeam-rs/crossbeam#636
Closes: #7

src/lib.rs

@@ -10,8 +10,9 @@
 //!
 //! Cache lines are assumed to be N bytes long, depending on the architecture:
 //!
-//! * On x86-64 and aarch64, N = 128.
-//! * On all others, N = 64.
+//! * On x86-64, aarch64, and powerpc64, N = 128.
+//! * On arm, mips, mips64, and riscv64, N = 32.
+//! * On s390x, N = 256.
 //!
 //! Note that N is just a reasonable guess and is not guaranteed to match the actual cache line
 //! length of the machine the program is running on.
@@ -67,14 +68,63 @@ use core::ops::{Deref, DerefMut};
 // - 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 lines.
+// 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/
 //
-#[cfg_attr(any(target_arch = "x86_64", target_arch = "aarch64"), repr(align(128)))]
+// 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")),
+    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(Clone, Copy, Default, Hash, PartialEq, Eq)]