[Xen-devel] [PATCH2/6] cpuidle: reduce redundant cost in cstate_restore_tsc for nonstop tsc

["Wei, Gang" <gang.wei@xxxxxxxxx>]

cpuidle: reduce redundant cost in cstate_restore_tsc for nonstop tsc

Signed-off-by: Wei Gang <gang.wei@xxxxxxxxx>

diff -r a73188d7fadc xen/arch/x86/time.c
--- a/xen/arch/x86/time.c       Sun Jun 13 06:47:31 2010 +0800
+++ b/xen/arch/x86/time.c       Sun Jun 13 06:53:45 2010 +0800
@@ -664,13 +664,16 @@ static void __init init_platform_timer(v
 
 void cstate_restore_tsc(void)
 {
-    struct cpu_time *t = &this_cpu(cpu_time);
-    struct time_scale sys_to_tsc = scale_reciprocal(t->tsc_scale);
+    struct cpu_time *t;
+    struct time_scale sys_to_tsc;
     s_time_t stime_delta;
     u64 new_tsc;
 
     if ( boot_cpu_has(X86_FEATURE_NONSTOP_TSC) )
         return;
+
+    t = &this_cpu(cpu_time);
+    sys_to_tsc = scale_reciprocal(t->tsc_scale);
 
     stime_delta = read_platform_stime() - t->stime_master_stamp;
     if ( stime_delta < 0 )

Attachment: 2-cpuidle-fix-cstate_restore_tsc.patch
Description: 2-cpuidle-fix-cstate_restore_tsc.patch

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