[rtems commit] score: Optimize per-processor data placement

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    9e4f21b927e8a81df8044806e88128388911e123
Changeset: http://git.rtems.org/rtems/commit/?id=9e4f21b927e8a81df8044806e88128388911e123

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Sat Feb  1 15:42:27 2020 +0100

score: Optimize per-processor data placement

Only align per-processor data in SMP configurations.

---

 cpukit/score/src/wkspace.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/cpukit/score/src/wkspace.c b/cpukit/score/src/wkspace.c
index 0834438..d363b8d 100644
--- a/cpukit/score/src/wkspace.c
+++ b/cpukit/score/src/wkspace.c
@@ -37,7 +37,14 @@
 
 RTEMS_LINKER_RWSET(
   _Per_CPU_Data,
-  RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES ) char
+#if defined(RTEMS_SMP)
+  /*
+   * In SMP configurations, prevent false cache line sharing of per-processor
+   * data with a proper alignment.
+   */
+  RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
+#endif
+  char
 );
 
 Heap_Control _Workspace_Area;