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* [Patch] Fix the slow wall clock time issue in x64 SMP Vista
@ 2007-01-10 11:29 Cui, Dexuan
  2007-01-10 11:36 ` Keir Fraser
  0 siblings, 1 reply; 10+ messages in thread
From: Cui, Dexuan @ 2007-01-10 11:29 UTC (permalink / raw)
  To: xen-devel; +Cc: Keir Fraser

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In x64 SMP Vista HVM guest (vcpus=2 in the configuration file), the wall
clock time is 50% slower than that in the real world. The attached patch
fixes the issue.

-- Dexuan

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>

[-- Attachment #2: hpet.c.diff --]
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diff -r 3157b54eb465 xen/arch/x86/hvm/hpet.c
--- a/xen/arch/x86/hvm/hpet.c	Thu Jan 04 16:34:19 2007 +0000
+++ b/xen/arch/x86/hvm/hpet.c	Wed Jan 10 16:50:52 2007 +0800
@@ -144,7 +144,7 @@ static void hpet_stop_timer(HPETState *h
 
 static void hpet_set_timer(HPETState *h, unsigned int tn)
 {
-    uint64_t tn_cmp, cur_tick;
+    uint64_t tn_cmp, cur_tick, scheduled, passed;
 
     ASSERT(tn < HPET_TIMER_NUM);
     
@@ -167,11 +167,25 @@ static void hpet_set_timer(HPETState *h,
         cur_tick = (uint32_t)cur_tick;
     }
 
-    if ( (int64_t)(tn_cmp - cur_tick) > 0 )
-        set_timer(&h->timers[tn], NOW() +
-                  hpet_tick_to_ns(h, tn_cmp-cur_tick));
-    else
-        set_timer(&h->timers[tn], NOW());
+    scheduled = tn_cmp - cur_tick;
+    if ( (int64_t)scheduled < 0 )
+    {
+        passed = cur_tick - tn_cmp;
+
+         /* the number of HPET tick that stands for
+          * 1/(2^10) second, namely, 0.9765625 millisecond */
+        #define  hpet_tiny_time_span  (h->tsc_freq >> 10)
+        if ( passed < hpet_tiny_time_span )
+             scheduled = 0;
+        else
+        {
+            if ( timer_is_32bit(h, tn) )
+                scheduled = (uint32_t)scheduled;
+            else
+                scheduled = (uint64_t)scheduled;
+        }
+    }
+    set_timer(&h->timers[tn], NOW() + hpet_tick_to_ns(h, scheduled));
 }
 
 static inline uint64_t hpet_fixup_reg(

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^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2007-01-11 13:29 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-01-10 11:29 [Patch] Fix the slow wall clock time issue in x64 SMP Vista Cui, Dexuan
2007-01-10 11:36 ` Keir Fraser
2007-01-10 11:53   ` Cui, Dexuan
2007-01-10 12:00     ` [Patch] Fix the slow wall clock time issue in x64 SMPVista Cui, Dexuan
2007-01-10 13:49       ` Keir Fraser
2007-01-10 12:02     ` [Patch] Fix the slow wall clock time issue in x64 SMP Vista Keir Fraser
2007-01-10 13:09       ` Cui, Dexuan
2007-01-10 13:45         ` Keir Fraser
2007-01-11 13:29         ` [Patch] Fix the slow wall clock time issue in x64 SMPVista Dong, Eddie
2007-01-10 14:42       ` [Patch] Fix the slow wall clock time issue in x64SMP Vista Dong, Eddie

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