xen: Implement sched_clock
Implement xen_sched_clock, which returns the number of ns the current
vcpu has been actually in an unstolen state (ie, running or blocked,
vs runnable-but-not-running, or offline) since boot.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Cc: john stultz <johnstul@us.ibm.com>
diff --git a/arch/i386/xen/time.c b/arch/i386/xen/time.c
index acbfd99..2aab44b 100644
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -28,6 +28,8 @@
#define TIMER_SLOP 100000
#define NS_PER_TICK (1000000000LL / HZ)
+static cycle_t xen_clocksource_read(void);
+
/* These are perodically updated in shared_info, and then copied here. */
struct shadow_time_info {
u64 tsc_timestamp; /* TSC at last update of time vals. */
@@ -169,6 +171,29 @@
account_steal_time(idle_task(smp_processor_id()), ticks);
}
+/*
+ * Xen sched_clock implementation. Returns the number of unstolen
+ * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
+ * states.
+ */
+unsigned long long xen_sched_clock(void)
+{
+ struct vcpu_runstate_info state;
+ cycle_t now = xen_clocksource_read();
+ s64 offset;
+
+ get_runstate_snapshot(&state);
+
+ WARN_ON(state.state != RUNSTATE_running);
+
+ offset = now - state.state_entry_time;
+ if (offset < 0)
+ offset = 0;
+
+ return state.time[RUNSTATE_blocked] +
+ state.time[RUNSTATE_running] +
+ offset;
+}
/* Get the CPU speed from Xen */
@@ -261,7 +286,7 @@
return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
}
-cycle_t xen_clocksource_read(void)
+static cycle_t xen_clocksource_read(void)
{
struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
cycle_t ret;