From 29719ace5192ff5c2d81c29d1947e32d7889f62b Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 14 Jun 2023 10:35:24 -0400
Subject: config: Add macros for false/true sharing sizes

---
 src/config.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

(limited to 'src/config.h')

diff --git a/src/config.h b/src/config.h
index dbe3c74..73348ac 100644
--- a/src/config.h
+++ b/src/config.h
@@ -191,6 +191,29 @@ static inline size_t flex_sizeof_impl(size_t align, size_t min, size_t offset, s
 	return ret;
 }
 
+/**
+ * False sharing/destructive interference/largest cache line size.
+ */
+#ifdef __GCC_DESTRUCTIVE_SIZE
+#  define FALSE_SHARING_SIZE __GCC_DESTRUCTIVE_SIZE
+#else
+#  define FALSE_SHARING_SIZE 64
+#endif
+
+/**
+ * True sharing/constructive interference/smallest cache line size.
+ */
+#ifdef __GCC_CONSTRUCTIVE_SIZE
+#  define TRUE_SHARING_SIZE __GCC_CONSTRUCTIVE_SIZE
+#else
+#  define TRUE_SHARING_SIZE 64
+#endif
+
+/**
+ * Alignment specifier that avoids false sharing.
+ */
+#define cache_align alignas(FALSE_SHARING_SIZE)
+
 // Wrappers for attributes
 
 /**
-- 
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