提交 1aec1c55 编写于 作者: I Isaku Yamahata 提交者: Tony Luck

ia64/pv_ops/xen/pv_time_ops: implement sched_clock.

paravirtualize sched_clock.
Signed-off-by: NIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: NTony Luck <tony.luck@intel.com>
上级 f927da17
......@@ -175,10 +175,58 @@ static void xen_itc_jitter_data_reset(void)
} while (unlikely(ret != lcycle));
}
/* based on xen_sched_clock() in arch/x86/xen/time.c. */
/*
* This relies on HAVE_UNSTABLE_SCHED_CLOCK. If it can't be defined,
* something similar logic should be implemented here.
*/
/*
* Xen sched_clock implementation. Returns the number of unstolen
* nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
* states.
*/
static unsigned long long xen_sched_clock(void)
{
struct vcpu_runstate_info runstate;
unsigned long long now;
unsigned long long offset;
unsigned long long ret;
/*
* Ideally sched_clock should be called on a per-cpu basis
* anyway, so preempt should already be disabled, but that's
* not current practice at the moment.
*/
preempt_disable();
/*
* both ia64_native_sched_clock() and xen's runstate are
* based on mAR.ITC. So difference of them makes sense.
*/
now = ia64_native_sched_clock();
get_runstate_snapshot(&runstate);
WARN_ON(runstate.state != RUNSTATE_running);
offset = 0;
if (now > runstate.state_entry_time)
offset = now - runstate.state_entry_time;
ret = runstate.time[RUNSTATE_blocked] +
runstate.time[RUNSTATE_running] +
offset;
preempt_enable();
return ret;
}
struct pv_time_ops xen_time_ops __initdata = {
.init_missing_ticks_accounting = xen_init_missing_ticks_accounting,
.do_steal_accounting = xen_do_steal_accounting,
.clocksource_resume = xen_itc_jitter_data_reset,
.sched_clock = xen_sched_clock,
};
/* Called after suspend, to resume time. */
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册