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Commit 1aec1c55 authored by Isaku Yamahata's avatar Isaku Yamahata Committed by Tony Luck
Browse files

ia64/pv_ops/xen/pv_time_ops: implement sched_clock. 



paravirtualize sched_clock.

Signed-off-by: default avatarIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent f927da17

arch/ia64/xen/time.c

+48 −0
Original line number Original line Diff line number Diff line
@@ -175,10 +175,58 @@ static void xen_itc_jitter_data_reset(void) 
	} while (unlikely(ret != lcycle));

	} 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 = {

struct pv_time_ops xen_time_ops __initdata = {

	.init_missing_ticks_accounting	= xen_init_missing_ticks_accounting,

	.init_missing_ticks_accounting	= xen_init_missing_ticks_accounting,

	.do_steal_accounting		= xen_do_steal_accounting,

	.do_steal_accounting		= xen_do_steal_accounting,

	.clocksource_resume		= xen_itc_jitter_data_reset,

	.clocksource_resume		= xen_itc_jitter_data_reset,

	.sched_clock			= xen_sched_clock,

};

};





/* Called after suspend, to resume time.  */

/* Called after suspend, to resume time.  */