[Qemu-devel] [PATCH] Revert "icount: remove obsolete warp call"

[Paolo Bonzini <pbonzini@redhat.com>]

QEMU running with options "-icount,sleep=off -rtc clock=vm" doesn't
execute emulation at maximum possible speed.
Target virtual clock may run faster or slower than realtime clock by N
times, where N value depends on various unrelated conditions (i.e. random
from the user point of view), or possibly the target hangs completely.
Bisection shows commit 281b2201e4 ("icount: remove obsolete warp call",
2016-03-15) to be the culprit, revert it.

Suggested-by: Artem Pisarenko <artem.k.pisarenko@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 cpus.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cpus.c b/cpus.c
index 361678e459..2872e7e37c 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1224,6 +1224,10 @@ static void qemu_tcg_rr_wait_io_event(CPUState *cpu)
 {
     while (all_cpu_threads_idle()) {
         stop_tcg_kick_timer();
+
+        /* Start accounting real time to the virtual clock if the CPUs
+           are idle.  */
+        qemu_clock_warp(QEMU_CLOCK_VIRTUAL);
         qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
     }
 
-- 
2.17.1