Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f8eca41f authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
Browse files

xen: measure how long spinlocks spend blocking 



Measure how long spinlocks spend blocked.  Also rename some fields to
be more consistent.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1e696f63

arch/x86/xen/spinlock.c

+42 −20
Original line number Diff line number Diff line
@@ -29,12 +29,14 @@ static struct xen_spinlock_stats 
	u32 released_slow;

	u32 released_slow_kicked;



#define HISTO_BUCKETS	20

	u32 histo_spin_fast[HISTO_BUCKETS+1];

	u32 histo_spin[HISTO_BUCKETS+1];



	u64 spinning_time;

	u64 total_time;

#define HISTO_BUCKETS	30

	u32 histo_spin_total[HISTO_BUCKETS+1];

	u32 histo_spin_spinning[HISTO_BUCKETS+1];

	u32 histo_spin_blocked[HISTO_BUCKETS+1];



	u64 time_total;

	u64 time_spinning;

	u64 time_blocked;

} spinlock_stats;



static u8 zero_stats;
@@ -70,20 +72,28 @@ static void __spin_time_accum(u64 delta, u32 *array) 
		array[HISTO_BUCKETS]++;

}



static inline void spin_time_accum_fast(u64 start)

static inline void spin_time_accum_spinning(u64 start)

{

	u32 delta = xen_clocksource_read() - start;



	__spin_time_accum(delta, spinlock_stats.histo_spin_spinning);

	spinlock_stats.time_spinning += delta;

}



static inline void spin_time_accum_total(u64 start)

{

	u32 delta = xen_clocksource_read() - start;



	__spin_time_accum(delta, spinlock_stats.histo_spin_fast);

	spinlock_stats.spinning_time += delta;

	__spin_time_accum(delta, spinlock_stats.histo_spin_total);

	spinlock_stats.time_total += delta;

}



static inline void spin_time_accum(u64 start)

static inline void spin_time_accum_blocked(u64 start)

{

	u32 delta = xen_clocksource_read() - start;



	__spin_time_accum(delta, spinlock_stats.histo_spin);

	spinlock_stats.total_time += delta;

	__spin_time_accum(delta, spinlock_stats.histo_spin_blocked);

	spinlock_stats.time_blocked += delta;

}

#else  /* !CONFIG_XEN_DEBUG_FS */

#define TIMEOUT			(1 << 10)
@@ -94,10 +104,13 @@ static inline u64 spin_time_start(void) 
	return 0;

}



static inline void spin_time_accum_fast(u64 start)

static inline void spin_time_accum_total(u64 start)

{

}

static inline void spin_time_accum_spinning(u64 start)

{

}

static inline void spin_time_accum(u64 start)

static inline void spin_time_accum_blocked(u64 start)

{

}

#endif  /* CONFIG_XEN_DEBUG_FS */
@@ -175,11 +188,14 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl 
	int irq = __get_cpu_var(lock_kicker_irq);

	int ret;

	unsigned long flags;

	u64 start;



	/* If kicker interrupts not initialized yet, just spin */

	if (irq == -1)

		return 0;



	start = spin_time_start();



	/* announce we're spinning */

	prev = spinning_lock(xl);
@@ -230,6 +246,8 @@ static noinline int xen_spin_lock_slow(struct raw_spinlock *lock, bool irq_enabl 
out:

	raw_local_irq_restore(flags);

	unspinning_lock(xl, prev);

	spin_time_accum_blocked(start);



	return ret;

}
@@ -262,12 +280,12 @@ static inline void __xen_spin_lock(struct raw_spinlock *lock, bool irq_enable) 
		    : "1" (1)

		    : "memory");



		spin_time_accum_fast(start_spin_fast);

		spin_time_accum_spinning(start_spin_fast);



	} while (unlikely(oldval != 0 &&

			  (TIMEOUT == ~0 || !xen_spin_lock_slow(lock, irq_enable))));



	spin_time_accum(start_spin);

	spin_time_accum_total(start_spin);

}



static void xen_spin_lock(struct raw_spinlock *lock)
@@ -385,14 +403,18 @@ static int __init xen_spinlock_debugfs(void) 
			   &spinlock_stats.released_slow_kicked);



	debugfs_create_u64("time_spinning", 0444, d_spin_debug,

			   &spinlock_stats.spinning_time);

			   &spinlock_stats.time_spinning);

	debugfs_create_u64("time_blocked", 0444, d_spin_debug,

			   &spinlock_stats.time_blocked);

	debugfs_create_u64("time_total", 0444, d_spin_debug,

			   &spinlock_stats.total_time);

			   &spinlock_stats.time_total);



	xen_debugfs_create_u32_array("histo_total", 0444, d_spin_debug,

				     spinlock_stats.histo_spin, HISTO_BUCKETS + 1);

				     spinlock_stats.histo_spin_total, HISTO_BUCKETS + 1);

	xen_debugfs_create_u32_array("histo_spinning", 0444, d_spin_debug,

				     spinlock_stats.histo_spin_fast, HISTO_BUCKETS + 1);

				     spinlock_stats.histo_spin_spinning, HISTO_BUCKETS + 1);

	xen_debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,

				     spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);



	return 0;

}