AK: Allow alignment to cache line size with CACHE_ALIGNED

This is particularly important to avoid false sharing, which thrashes performance when two process-shared atomics are on the same cache line.
Author: https://github.com/kleinesfilmroellchen Commit: https://github.com/SerenityOS/serenity/commit/65b338ad04 Pull-request: https://github.com/SerenityOS/serenity/pull/12102 Issue: https://github.com/SerenityOS/serenity/issues/11882 Reviewed-by: https://github.com/ADKaster Reviewed-by: https://github.com/Hendiadyoin1 Reviewed-by: https://github.com/bgianfo Reviewed-by: https://github.com/linusg
2022-03-04 14:57:38 +01:00 · 2022-03-04 14:57:38 +01:00 · 65b338ad04 · 2024-07-17 11:37:27 +09:00
commit 65b338ad04
parent d463f6e00a
1 changed files with 13 additions and 0 deletions
--- a/AK/Platform.h
+++ b/AK/Platform.h
@ -110,3 +110,16 @@ extern "C" {
 #    define CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC
 #    define CLOCK_REALTIME_COARSE CLOCK_REALTIME
 #endif
+
+#ifndef SYSTEM_CACHE_ALIGNMENT_SIZE
+#    if ARCH(AARCH64) || ARCH(x86_64)
+#        define SYSTEM_CACHE_ALIGNMENT_SIZE 64
+#    else
+#        define SYSTEM_CACHE_ALIGNMENT_SIZE 128
+#    endif
+#endif /* SYSTEM_CACHE_ALIGNMENT_SIZE */
+
+#ifdef CACHE_ALIGNED
+#    undef CACHE_ALIGNED
+#endif
+#define CACHE_ALIGNED alignas(SYSTEM_CACHE_ALIGNMENT_SIZE)