[Xen-changelog] [xen-unstable] cpuidle: reduce redundant cost in cstate_restore_tsc for nonstop tsc

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1276761055 -3600
# Node ID 6fffbb86acae27f5a742884b5d3b5a5c73b4ed15
# Parent  7a00c0bd4fc131fb4de5df9f3fdc4e48a29dd5f9
cpuidle: reduce redundant cost in cstate_restore_tsc for nonstop tsc

Signed-off-by: Wei Gang <gang.wei@xxxxxxxxx>
---
 xen/arch/x86/time.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff -r 7a00c0bd4fc1 -r 6fffbb86acae xen/arch/x86/time.c
--- a/xen/arch/x86/time.c       Thu Jun 17 08:50:18 2010 +0100
+++ b/xen/arch/x86/time.c       Thu Jun 17 08:50:55 2010 +0100
@@ -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 )

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