$ git diff google_qemu_stream isec_nathan_timer_tweak
diff --git a/qemu_timers.c b/qemu_timers.c
index 2dc0806..d521315 100644
--- a/qemu_timers.c
+++ b/qemu_timers.c
@@ -29,6 +29,13 @@ QEMUClock *vm_clock;
 /***********************************************************/
 /* real time host monotonic timer */

+/* Hacked by nathan@isecpartners.com to prevent busy spin during clone
+ * on a slow linux vm guest:
+ */
+#define ORIGINAL_QEMU_UNIX_USEC 999
+#define TWEAKED_QEMU_UNIX_USEC 9999
+#define QEMU_UNIX_USEC TWEAKED_QEMU_UNIX_USEC
+
 /* digit: the following two variables are used to implement high-resolution
  * poll-based interrupts. the idea is to be able to generate an emulated
  * interrupt every millisecond, even on non-Linux platforms which don't have
@@ -917,9 +924,9 @@ static int unix_start_timer(struct qemu_alarm_timer *t)

     itv.it_interval.tv_sec = 0;
     /* for i386 kernel 2.6 to get 1 ms */
-    itv.it_interval.tv_usec = 999;
+    itv.it_interval.tv_usec = QEMU_UNIX_USEC;
     itv.it_value.tv_sec = 0;
-    itv.it_value.tv_usec = 10 * 1000;
+    itv.it_value.tv_usec = 10 * (QEMU_TIMER_REALTIME + 1);

     err = setitimer(ITIMER_REAL, &itv, NULL);
     if (err)