main: force enabling of I/O thread

Enabling the I/O thread by default seems like an important part of declaring
1.0.  Besides allowing true SMP support with KVM, the I/O thread means that the
TCG VCPU doesn't have to multiplex itself with the I/O dispatch routines which
currently requires a (racey) signal based alarm system.

I know there have been concerns about performance.  I think so far the ones that
have come up (virtio-net) are most likely due to secondary reasons like
decreased batching.

I think we ought to force enabling I/O thread early in 1.0 development and
commit to resolving any lingering issues.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 0 insertions, 53 deletions

diff --git a/qemu-timer.c b/qemu-timer.c
index 19313d3b00..46dd483fdd 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -101,22 +101,6 @@ static int64_t cpu_get_clock(void)
     }
 }
 
-#ifndef CONFIG_IOTHREAD
-static int64_t qemu_icount_delta(void)
-{
-    if (!use_icount) {
-        return 5000 * (int64_t) 1000000;
-    } else if (use_icount == 1) {
-        /* When not using an adaptive execution frequency
-           we tend to get badly out of sync with real time,
-           so just delay for a reasonable amount of time.  */
-        return 0;
-    } else {
-        return cpu_get_icount() - cpu_get_clock();
-    }
-}
-#endif
-
 /* enable cpu_get_ticks() */
 void cpu_enable_ticks(void)
 {
@@ -688,9 +672,7 @@ void configure_icount(const char *option)
     if (!option)
         return;
 
-#ifdef CONFIG_IOTHREAD
     vm_clock->warp_timer = qemu_new_timer_ns(rt_clock, icount_warp_rt, NULL);
-#endif
 
     if (strcmp(option, "auto") != 0) {
         icount_time_shift = strtol(option, NULL, 0);
@@ -1178,41 +1160,6 @@ void quit_timers(void)
 
 int qemu_calculate_timeout(void)
 {
-#ifndef CONFIG_IOTHREAD
-    int timeout;
-
-    if (!vm_running)
-        timeout = 5000;
-    else {
-     /* XXX: use timeout computed from timers */
-        int64_t add;
-        int64_t delta;
-        /* Advance virtual time to the next event.  */
-	delta = qemu_icount_delta();
-        if (delta > 0) {
-            /* If virtual time is ahead of real time then just
-               wait for IO.  */
-            timeout = (delta + 999999) / 1000000;
-        } else {
-            /* Wait for either IO to occur or the next
-               timer event.  */
-            add = qemu_next_icount_deadline();
-            /* We advance the timer before checking for IO.
-               Limit the amount we advance so that early IO
-               activity won't get the guest too far ahead.  */
-            if (add > 10000000)
-                add = 10000000;
-            delta += add;
-            qemu_icount += qemu_icount_round (add);
-            timeout = delta / 1000000;
-            if (timeout < 0)
-                timeout = 0;
-        }
-    }
-
-    return timeout;
-#else /* CONFIG_IOTHREAD */
     return 1000;
-#endif
 }