From 5d1048f9068aac5a61bc6ab3fb2b561db84a982c Mon Sep 17 00:00:00 2001
From: kvn <unknown>
Date: Thu, 17 Mar 2011 12:08:01 -0700
Subject: [PATCH] 7028394: Newer AMD Processor Prefetch Defaults Summary: This
 new default has shown improvement across many workloads. Reviewed-by: kvn
 Contributed-by: tom.deneau@amd.com

---
 src/cpu/x86/vm/vm_version_x86.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/cpu/x86/vm/vm_version_x86.cpp b/src/cpu/x86/vm/vm_version_x86.cpp
index df40c5638..3321d5486 100644
--- a/src/cpu/x86/vm/vm_version_x86.cpp
+++ b/src/cpu/x86/vm/vm_version_x86.cpp
@@ -436,6 +436,13 @@ void VM_Version::get_processor_features() {
         UseCountLeadingZerosInstruction = true;
       }
     }
+
+    // On family 21 processors default is no sw prefetch
+    if ( cpu_family() == 21 ) {
+      if (FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
+        AllocatePrefetchStyle = 0;
+      }
+    }
   }
 
   if( is_intel() ) { // Intel cpus specific settings
-- 
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