[Xen-devel] [PATCH v2] use INT64_MAX as max expiration

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Change from v1:
According to Jan and Stefano's comments, drop the previous logic which setting 
the value in an arbitrary way and use Stefano's suggestion instead.

Currently, the max expiration time is 2147483647ns(INT32_MAX ns)n This is 
enough when guest is busy, but when guest is idle, the next timer will be later 
than INT32_MAX ns. And those meaningless alarm will harm the pkg C-state.

Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
---
 vl.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/vl.c b/vl.c
index be8587a..a9b7a0d 100644
--- a/vl.c
+++ b/vl.c
@@ -1410,8 +1410,7 @@ static int64_t qemu_next_deadline(void)
         delta = active_timers[QEMU_TIMER_VIRTUAL]->expire_time -
                      qemu_get_clock(vm_clock);
     } else {
-        /* To avoid problems with overflow limit this to 2^32.  */
-        delta = INT32_MAX;
+        delta = INT64_MAX;
     }

     if (delta < 0)
@@ -1427,9 +1426,11 @@ static uint64_t qemu_next_deadline_dyntick(void)
     int64_t rtdelta;

     if (use_icount)
-        delta = INT32_MAX;
-    else
-        delta = (qemu_next_deadline() + 999) / 1000;
+        delta = INT64_MAX;
+    else {
+        delta = qemu_next_deadline();
+        delta = (delta / 1000) + (delta % 1000 > 0 ? 1 : 0);
+    }

     if (active_timers[QEMU_TIMER_REALTIME]) {
         rtdelta = (active_timers[QEMU_TIMER_REALTIME]->expire_time -
--
1.7.1


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