Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

[mirror_qemu.git] / cpus.c

diff --git a/cpus.c b/cpus.c
index 85cd451a86a9c38718f5ca85581f1f36dfcd1f29..d2c61ff1558aa83894ffb40233600859f937c40b 100644 (file)
--- a/cpus.c
+++ b/cpus.c
@@ -77,6 +77,8 @@
 
 #endif /* CONFIG_LINUX */
 
+static QemuMutex qemu_global_mutex;
+
 int64_t max_delay;
 int64_t max_advance;
 
@@ -782,7 +784,7 @@ static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque)
 {
     double pct;
     double throttle_ratio;
-    long sleeptime_ns;
+    int64_t sleeptime_ns, endtime_ns;
 
     if (!cpu_throttle_get_percentage()) {
         return;
@@ -790,11 +792,20 @@ static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque)
 
     pct = (double)cpu_throttle_get_percentage()/100;
     throttle_ratio = pct / (1 - pct);
-    sleeptime_ns = (long)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS);
-
-    qemu_mutex_unlock_iothread();
-    g_usleep(sleeptime_ns / 1000); /* Convert ns to us for usleep call */
-    qemu_mutex_lock_iothread();
+    /* Add 1ns to fix double's rounding error (like 0.9999999...) */
+    sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1);
+    endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns;
+    while (sleeptime_ns > 0 && !cpu->stop) {
+        if (sleeptime_ns > SCALE_MS) {
+            qemu_cond_timedwait(cpu->halt_cond, &qemu_global_mutex,
+                                sleeptime_ns / SCALE_MS);
+        } else {
+            qemu_mutex_unlock_iothread();
+            g_usleep(sleeptime_ns / SCALE_US);
+            qemu_mutex_lock_iothread();
+        }
+        sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+    }
     atomic_set(&cpu->throttle_thread_scheduled, 0);
 }
 
@@ -1172,8 +1183,6 @@ static void qemu_init_sigbus(void)
 }
 #endif /* !CONFIG_LINUX */
 
-static QemuMutex qemu_global_mutex;
-
 static QemuThread io_thread;
 
 /* cpu creation */