On 02/15/2011 09:56 PM, Marcelo Tosatti wrote:
Note: to be applied to uq/master.
In icount mode, halt emulation should take into account the nearest
event when sleeping.
I agree with Jan that this patch is not the best solution, if not incorrect.
However, in the iothread, the main loop can kick the VCPU thread instead
of running cpu_exec_all like it does in non-iothread mode. Something
like this:
diff --git a/vl.c b/vl.c
index b436952..7835317 100644
--- a/vl.c
+++ b/vl.c
@@ -1425,7 +1425,9 @@ static void main_loop(void)
qemu_main_loop_start();
for (;;) {
-#ifndef CONFIG_IOTHREAD
+#ifdef CONFIG_IOTHREAD
+ qemu_cpu_kick(first_cpu);
+#else
nonblocking = cpu_exec_all();
if (vm_request_pending()) {
nonblocking = true;
I don't like this 100% because it relies on the fact that there is only
one TCG execution thread. In a multithreaded world you would:
1) have each CPU register its own instruction counter;
2) have each CPU register its own QEMU_CLOCK_REALTIME timer based on
qemu_icount_delta() and arm it just before going to sleep; the timer
kicks the CPU.
3) remove all icount business from qemu_calculate_timeout.
Item (3) is what makes me prefer my patch above (if it works) to
Marcelo's. Marcelo's patch is tying even more qemu_calculate_timeout to
the icount. So if anything, a patch tweaking the timedwait like
Marcelo's should use something based on qemu_icount_delta().
Paolo
