[Qemu-devel] [RFC PATCH v5 08/31] icount: improve enable/disable ticks

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

This patch eliminates call of the cpu_get_real_ticks while enabling
or disabling the virtual timer in icount mode. These calls are used
for cpu_ticks_offset which is not needed in this mode.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 cpus.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/cpus.c b/cpus.c
index 492e19a..43ae7fc 100644
--- a/cpus.c
+++ b/cpus.c
@@ -267,8 +267,10 @@ void cpu_enable_ticks(void)
     /* Here, the really thing protected by seqlock is cpu_clock_offset. */
     seqlock_write_lock(&timers_state.vm_clock_seqlock);
     if (!timers_state.cpu_ticks_enabled) {
-        timers_state.cpu_ticks_offset -= cpu_get_real_ticks();
-        timers_state.cpu_clock_offset -= get_clock();
+        if (!use_icount) {
+            timers_state.cpu_ticks_offset -= cpu_get_real_ticks();
+            timers_state.cpu_clock_offset -= get_clock();
+        }
         timers_state.cpu_ticks_enabled = 1;
     }
     seqlock_write_unlock(&timers_state.vm_clock_seqlock);
@@ -283,8 +285,10 @@ void cpu_disable_ticks(void)
     /* Here, the really thing protected by seqlock is cpu_clock_offset. */
     seqlock_write_lock(&timers_state.vm_clock_seqlock);
     if (timers_state.cpu_ticks_enabled) {
-        timers_state.cpu_ticks_offset += cpu_get_real_ticks();
-        timers_state.cpu_clock_offset = cpu_get_clock_locked();
+        if (!use_icount) {
+            timers_state.cpu_ticks_offset += cpu_get_real_ticks();
+            timers_state.cpu_clock_offset = cpu_get_clock_locked();
+        }
         timers_state.cpu_ticks_enabled = 0;
     }
     seqlock_write_unlock(&timers_state.vm_clock_seqlock);