On Sat, Jul 20, 2013 at 07:06:38PM +0100, Alex Bligh wrote:
> Add utility functions to qemu-timer.c for nanosecond timing.
>
> Ensure we keep track of all QEMUClocks on a list.
>
> Add qemu_clock_deadline_ns and qemu_clock_deadline_all_ns to
> calculate deadlines to nanosecond accuracy.
>
> Add utility function qemu_soonest_timeout to calculate soonest deadline.
>
> Add qemu_timeout_ns_to_ms to convert a timeout in nanoseconds back to
> milliseconds for when ppoll is not used.
Please split this into smaller patches. There are several logical
changes happening here.
> @@ -61,6 +71,15 @@ int64_t cpu_get_ticks(void);
> void cpu_enable_ticks(void);
> void cpu_disable_ticks(void);
>
> +static inline int64_t qemu_soonest_timeout(int64_t timeout1, int64_t
> timeout2)
> +{
> + /* we can abuse the fact that -1 (which means infinite) is a maximal
> + * value when cast to unsigned. As this is disgusting, it's kept in
> + * one inline function.
> + */
> + return ((uint64_t) timeout1 < (uint64_t) timeout2) ? timeout1 : timeout2;
The straightforward version isn't much longer than the commented casting trick:
if (timeout1 == -1) {
return timeout2;
} else if (timeout2 == -1) {
return timeout1;
} else {
return timeout1 < timeout2 ? timeout1 : timeout2;
}
> @@ -48,6 +44,8 @@ struct QEMUClock {
>
> int type;
> bool enabled;
> +
> + QLIST_ENTRY(QEMUClock) list;
I don't think global state is necessary. The
run_timers()/clock_deadline() users have QEMUClock references, they can
just call per-QEMUClock functions instead of requiring qemu-timers.c to
keep a list.
This way AioContext clocks are safe to use from threads.
> +void qemu_free_clock(QEMUClock *clock)
> +{
> + QLIST_REMOVE(clock, list);
> + g_free(clock);
assert that there are no timers left?
